annex b - mema district 1 regional hazard mitigation … · 2018-09-04 · annex b: desoto county...

ANNEX B DESOTO COUNTY

MEMA District 1 Regional Hazard Mitigation Plan DRAFT – October 2016

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This annex includes jurisdiction-specific information for DeSoto County and its participating municipalities. It consists of the following five subsections:

B.1 DeSoto County Community Profile

B.2 DeSoto County Risk Assessment

B.3 DeSoto County Vulnerability Assessment

B.4 DeSoto County Capability Assessment

B.5 DeSoto County Mitigation Strategy

B.1 DESOTO COUNTY COMMUNITY PROFILE

B.1.1 Geography and the Environment DeSoto County is located in north western Mississippi. It comprises one town and four cities, City of Hernando, City of Horn Lake, City of Olive Branch, City of Southaven, and Town of Walls, as well as many small unincorporated communities. An orientation map is provided as Figure B.1. The county is located to the east of the Mississippi River and north of Arkabutla Lake. The total area of the county is 497 square miles, 21 square miles of which is water area. Summer temperatures in the county range from highs of 90 degrees Fahrenheit (˚F) to lows in the 60s. Winter temperatures range from highs in the low to mid 50s to lows in 30˚F. Average annual rainfall is approximately 53 inches, with the wettest months being May and December.

ANNEX B: DESOTO COUNTY


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FIGURE B.1: DESOTO COUNTY ORIENTATION MAP

B.1.2 Population and Demographics According to the 2010 Census, DeSoto County has a population of 161,252 people. The county has seen an increase in population between 2000 and 2010, and the population density is 324 people per square mile. Population counts from the U.S. Census Bureau for 1990, 2000, and 2010 for the county and participating jurisdictions are presented in Table B.1.

TABLE B.1: POPULATION COUNTS FOR DESOTO COUNTY

Jurisdiction 1990 Census Population

2000 Census Population

2010 Census Population

% Change 2000-2010

DeSoto County 67,910 107,199 161,252 33.5%

Hernando 1,158 6,812 14,090 51.7%

Horn Lake 2,965 14,099 26,066 45.9%

Olive Branch 1,322 21,054 33,484 37.1%

Southaven 6,115 28,977 48,982 40.8%

Walls -- -- 1,162 --

Source: United States Census Bureau, 1990, 2000, and 2010 Census



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Based on the 2010 Census, the median age of residents of DeSoto County is 35 years. The racial characteristics of the county are presented in Table B.2. Whites make up the majority of the population in the county, accounting for 72 percent of the population.

TABLE B.2: DEMOGRAPHICS OF DESOTO COUNTY

Jurisdiction White, Percent (2010)

Black or African

American, Percent (2010)

American Indian or

Alaska Native, Percent (2010)

Asian, Percent (2010)

Native Hawaiian or Other Pacific

Islander, Percent (2010)

Other Race,

Percent (2010)

Two or More Races,

percent (2010)

Persons of

Hispanic Origin, Percent (2010)*

DeSoto County 72.2% 21.9% 0.3% 1.3% 0.1% 2.8% 1.6% 5.0%

Hernando 81.6% 13.1% 0.2% 1.0% 0.0% 3.0% 1.1% 5.5%

Horn Lake 59.0% 32.9% 0.4% 1.0% 0.0% 4.5% 2.3% 8.0%

Olive Branch 71.5% 23.1% 0.2% 1.3% 0.1% 2.4% 1.4% 4.2%

Southaven 71.0% 22.2% 0.3% 1.7% 0.1% 3.0% 1.7% 5.0%

Walls 34.7% 60.8% 0.2% 0.6% 0.0% 1.4% 2.3% 3.0%

*Hispanics may be of any race, so also are included in applicable race categories Source: United States Census Bureau, 2010 Census

B.1.3 Housing According to the 2010 U.S. Census, there are 61,634 housing units in DeSoto County, the majority of which are single family homes or mobile homes. Housing information for the county and five municipalities is presented in Table B.3. As shown in the table, all of the incorporated town and cities have similar percentages of seasonal housing units compared to the unincorporated county.

TABLE B.3: HOUSING CHARACTERISTICS OF DESOTO COUNTY

Jurisdiction Housing Units

(2000) Housing Units

(2010) Seasonal Units, Percent (2010)

Median Home Value (2010-2014)

DeSoto County 40,795 61,634 0.4% $151,200

Hernando 2,720 5,506 0.4% $170,500

Horn Lake 5,153 9,705 0.3% $94,900

Olive Branch 7,935 12,942 0.5% $163,100

Southaven 11,462 19,101 0.2% $137,800

Walls -- 440 0.4% $120,800

Source: United States Census Bureau, 2000 and 2010 Census and 2010-2014 American Community Survey 5-Year Estimates

B.1.4 Infrastructure

TRANSPORTATION In DeSoto County, Interstate 55 provides north-south access to areas in Memphis, Tennessee to north of New Orleans, Louisiana. DeSoto County contains Interstate 69 operating in the western area of the County. U.S. Highway 51 which is a north-south highway traveling from New Orleans, Louisiana north to



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the Wisconsin-Minnesota state border operates within DeSoto County. U.S. Highway 61, a north-south highway, travels through DeSoto County. DeSoto County contains six aircraft facilities. Olive Branch Public/Private Airport, in DeSoto County, is a privately owned but publicly used airport categorized as a general aviation reliever airport. Hernando Village Private/Public Airpark privately owned and publicly used has hanger space available to pilots and their aircraft. Finally, Eagles Ridge Private/Public will be open to the public soon. Vaiden Landing, Colonial, and Delta Flying Service Airports are all privately owned and for private use only airport facilities. The closest international airport is in Memphis, less than 15 miles away from the county. Multiple freight rail lines operate within DeSoto County. In northeastern DeSoto County the Burlington Northern Sante Fe Railway, a Class I Major railroad, operates. Grenada Railroad is a Class III Local railroad running through central DeSoto County. TN Terminal is another Class III Local railroad within DeSoto County.

UTILITIES Electrical power in DeSoto County is provided by the Coahoma electric power association. Entergy Utility serves DeSoto County. Northcentral Mississippi electric power association and South Mississippi electric power association serve DeSoto County. DeSoto County is provided service from Tallahatchie Valley electric power association, as well. Water and sewer service is provided by all of the participating towns and/or community based associations, but unincorporated areas often rely on septic systems and wells in DeSoto County. Southaven Water Department and Utilities Division provide services to the City of Southaven. Olive Branch Public Utilities provides service to the City of Olive Branch. Belmont Waster Association in an additional service provider located in the City of Hernando.

COMMUNITY FACILITIES There are a number of buildings and community facilities located throughout DeSoto County. According to the data collected for the vulnerability assessment (Section 6.4.1), there are 21 fire stations, 7 police stations, and 35 schools located within the county. There are two hospitals located in DeSoto County. Baptist Memorial Hospital-North Mississippi is a 242-bed general medical and surgical care facility serving northern Mississippi with an accredited rehabilitation facility. Methodist Olive Branch Hospital is a 100 bed hospital that opened in 2013. DeSoto County Museum located in the City of Hernando and contains exhibits related to civil war history and other history associated with the County. The City of Southaven, within DeSoto County, contains the Arena at Southaven which offers access to horse shows, rodeos, expos and trade shows. The City of Southaven also operated multiple different sports complex pertaining to football, baseball, softball, soccer and gold. The Snowden Grove Amphitheater in DeSoto County features summer music concerts and festivals. DeSoto County contains various water features that can be accessed for recreations in designated areas. These water features include Arkabutla Lake, Coldwater River, Mississippi Delta Bluffs, and the Mississippi River. Hernando DeSoto Park, within DeSoto County, features hiking and walking trails,



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river overlook, picnic area, boat parking and launch access to the Mississippi River. A variety of community parks throughout DeSoto County are operated and maintained by the County.

B.1.5 Land Use Many areas of DeSoto County are undeveloped or sparsely developed. There are several small incorporated municipalities located throughout the county, with a few larger hubs interspersed. These areas are where the county’s population is generally concentrated. The incorporated areas are also where many of the businesses, commercial uses, and institutional uses are located. Land uses in the balance of the county generally consist of rural residential development, agricultural uses, and recreational areas, although there are some notable exceptions in the larger municipalities. Local land use and associated regulations are further discussed in Section 7: Capability Assessment. North Delta Planning and Development District provides services related to regional planning, local technical assistance, and coordination and review of applications for federally sponsored programs within Northwest Mississippi. The purpose of the district is to promote economic development, encourage responsibility short and long term community planning, and to aid in general civic, social, and economic development.

B.1.6 Employment and Industry According to the U.S. Census Bureau’s American Community Survey (ACS), in 2014, DeSoto County had an average annual employment of 88,271 workers and an average unemployment rate of 5.7 percent (compared to 6.3 percent for the state). In 2014, the Education services, and health care and social assistance industry employed 20.5 percent of the county’s workforce followed by Transportation and warehousing, and utilities (12.8%); Manufacturing (10.7%); Retail trade (10.5%); and Arts, entertainment, and recreation, and accommodation and food services (10.3%). The average annual median household in 2014 for DeSoto County was $58,995 compared to $39,464 in the state of Mississippi.

B.2 DESOTO COUNTY RISK ASSESSMENT This subsection includes hazard profiles for each of the significant hazards identified in Section 4: Hazard Identification as they pertain to DeSoto County. Each hazard profile includes a description of the hazard’s location and extent, notable historical occurrences, and the probability of future occurrences. Additional information can be found in Section 5: Hazard Profiles.

FLOOD-RELATED HAZARDS

B.2.1 Dam and Levee Failure

LOCATION AND SPATIAL EXTENT According to the Mississippi Department of Environmental Quality, there are 26 high hazard dams in DeSoto County.1 Figure B.2 shows the location of these high hazard dam and Table B.4 lists them by name.

1 The list of high hazard dams obtained from the Mississippi Department of Environmental Quality was reviewed and amended

by local officials to the best of their knowledge.



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FIGURE B.2: DESOTO COUNTY HIGH HAZARD DAM LOCATIONS

Source: Mississippi Department of Environmental Quality

TABLE B.4: DESOTO COUNTY HIGH HAZARD DAMS Dam Name Hazard Potential

DeSoto County

APPLE CREEK DAM High

APPLE CREEK NORTH DAM High

ARKABUTLA DAM High

BLUE SPRINGS LAKE A DAM High

CENTRAL PARK LAKE DAM High

CROSS CREEK DAM - EAST LAKE DAM High

CROSS CREEK DAM - WEST LAKE DAM High

DEER TRACK LAKE DAM High

FOX LAKE DAM High

GRAYS CREEK LAKE #1 DAM High

HILDERBRANT LAKE DAM High

J E LYON POND DAM High

LAKE GREENBROOK DAM High



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Dam Name Hazard Potential

LAKE O' THE HILLS DAM High

MASON LAKE DAM High

MAYWOOD SUBDIVISION - SHAHKOKA DAM High

MAYWOOD SUBDIVISION - WOODLAND LAKE DAM High

MCINVALE LAKE DAM High

MEGAN DRIVE LAKE DAM High

R N VAN VULPEN POND DAM High

RAIN CLOUD LAKE DAM High

SHORT FORK POND DAM High

STONEHEDGE DAM High

WANITA MANN POND DAM High

WILL BOND INCORPORATED POND DAM High

WOODLAND LAKE DAM High


HISTORICAL OCCURRENCES According to the Mississippi State Hazard Mitigation Plan, there have been two dam failures reported in DeSoto County. Although no damage was reported with these events, several breach scenarios in the region could be catastrophic. Table B.5 below provides a brief description of the five reported dam failures.

TABLE B.5: DESOTO COUNTY DAM FAILURES (1982-2012) Date County Structure Name Cause of Failure

April 1994 DeSoto Strickland Lake Breached by Regulators

2005 DeSoto Allen Subdivision

Lake Animal penetration, causing dam to breach


PROBABILITY OF FUTURE OCCURRENCES Given the current dam inventory and historic data, a dam breach is unlikely (less than 1 percent annual probability) in the future. As has been demonstrated in the past, regular monitoring is necessary to prevent these events.

B.2.2 Erosion

LOCATION AND SPATIAL EXTENT Erosion in DeSoto County is typically caused by flash flooding events. Unlike coastal areas, areas of concern for erosion in DeSoto County are primarily rivers/streams and reservoirs. Generally, vegetation helps to prevent erosion in the area, and it is not an extreme threat to the county. At this time, there is no data available on localized areas of erosion so it is not possible to depict extent on a map.



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HISTORICAL OCCURRENCES Several sources were vetted to identify areas of erosion in DeSoto County. This includes searching local newspapers, interviewing local officials, and reviewing previous hazard mitigation plans. No major historical erosion occurrences were found in these sources.

PROBABILITY OF FUTURE OCCURRENCES Erosion remains a natural, dynamic, and continuous process for DeSoto County, and it will continue to occur. The annual probability level assigned for erosion is likely (between 10 and 100 percent annually).

B.2.3 Flood

LOCATION AND SPATIAL EXTENT There are areas in DeSoto County that are susceptible to flood events. Special flood hazard areas in the county were mapped using Geographic Information System (GIS) and FEMA Digital Flood Insurance Rate Maps (DFIRM).2 This includes Zone A (1-percent annual chance floodplain) and Zone AE (1-percent annual chance floodplain with elevation). According to GIS analysis, of the 494.7 square miles that make up DeSoto County, there are 121.2 square miles of land in zones A and AE (1-percent annual chance floodplain/100-year floodplain). These flood zone values account for 24.5 percent of the total land area in DeSoto County. It is important to note that while FEMA digital flood data is recognized as best available data for planning purposes, it does not always reflect the most accurate and up-to-date flood risk. Flooding and flood-related losses often do occur outside of delineated special flood hazard areas. Figure B.3 illustrates the location and extent of currently mapped special flood hazard areas for DeSoto County based on best available FEMA Digital Flood Insurance Rate Map (DFIRM) data.

2 The county-level DFIRM data used for DeSoto County were updated in 2010.



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FIGURE B.3: SPECIAL FLOOD HAZARD AREAS IN DESOTO COUNTY

Source: Federal Emergency Management Agency

HISTORICAL OCCURRENCES Floods were at least partially responsible for four disaster declarations in DeSoto County in 1973, 2001, and twice in 2011.3 Information from the National Climatic Data Center was used to ascertain additional historical flood events. The National Climatic Data Center reported a total of 60 events in DeSoto County since 1997.4 A summary of these events is presented in Table B.6. These events accounted for almost $11.8 million (2016 dollars) in property damage and two fatalities in the county.5 Specific information on flood events, including date, type of flooding, and deaths and injuries, can be found in Table B.7.

3 A complete listing of historical disaster declarations can be found in Section 4: Hazard Identification. 4 These flood events are only inclusive of those reported by the National Climatic Data Center (NCDC) from 1996 through

March 2016. It is likely that additional occurrences have occurred and have gone unreported. As additional local data becomes

available, this hazard profile will be amended. 5 Adjusted dollar values were calculated based on the average Consumer Price Index for a given calendar year. This index value

has been calculated every year since 1913. For 2016, the May 2016 monthly index was used.



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TABLE B.6: SUMMARY OF FLOOD OCCURRENCES IN DESOTO COUNTY

Location Number of

Occurrences Deaths/Injuries

Property Damage (2016)

Annualized Property Losses

Hernando 5 0/0 $26,675 $1,905

Horn Lake 7 0/0 $6,271,260 $447,947

Olive Branch 12 0/0 $61,281 $4,714

Southaven 6 0/0 $7,245 $381

Walls 1 0/0 $0 $0

Unincorporated Area 29 2/0 $5,390,792 $359,386

DESOTO COUNTY TOTAL

60 2/0 $11,757,253 $814,334

Source: National Climatic Data Center

TABLE B.7: HISTORICAL FLOOD EVENTS IN DESOTO COUNTY Location Date Type Deaths/Injuries Property Damage*

Hernando

HERNANDO 8/16/2002 Flood 0/0 $1,335

HERNANDO 4/4/2008 Flash Flood 0/0 $0



HERNANDO 7/3/2015 Flash Flood 0/0 $25,340

Horn Lake

HORN LAKE 9/19/2002 Flash Flood 0/0 $1,335




HORN LAKE 7/15/2005 Flash Flood 0/0 $6,150,435

HORN LAKE 7/30/2009 Flash Flood 0/0 $0


Olive Branch

OLIVE BRANCH 5/17/2003 Flash Flood 0/0 $1,306




OLIVE BRANCH 1/10/2008 Flash Flood 0/0 $0








South Haven

SOUTHAVEN 3/5/1997 Flash Flood 0/0 $2,994

SOUTH HAVEN 7/13/1998 Flood 0/0 $1,474

SOUTH HAVEN 4/3/1999 Flood 0/0 $1,442



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Location Date Type Deaths/Injuries Property Damage*

SOUTH HAVEN 7/12/2002 Flash Flood 0/0 $1,335

SOUTH HAVEN 5/2/2008 Flash Flood 0/0 $0

SOUTH HAVEN 7/16/2009 Flash Flood 0/0 $0

Walls

WALLS 6/6/2014 Flash Flood 0/0 $0

Unincorporated Area

DE SOTO (ZONE) 11/28/2001 Flood 1/0 $1,017,374

DE SOTO (ZONE) 12/12/2001 Flood 0/0 $1,357


COUNTYWIDE 10/10/2002 Flash Flood 1/0 $6,677


COUNTYWIDE 2/15/2004 Flash Flood 0/0 $1,272

HORN LAKE DESOTO ARP 3/31/2008 Flash Flood 0/0 $0

LYNCHBURG 4/11/2008 Flash Flood 0/0 $0


INGRAMS MILL 7/22/2008 Flash Flood 0/0 $5,579

HANDY CORNER 7/31/2008 Flash Flood 0/0 $0

NESBIT 7/31/2008 Flash Flood 0/0 $0

COCKRUM 5/6/2009 Flash Flood 0/0 $55,989

NESBIT 12/8/2009 Flash Flood 0/0 $0

LYNCHBURG 4/26/2011 Flash Flood 0/0 $267,001

PENTON 5/1/2011 Flood 0/0 $801,004

MILLER 9/2/2012 Flash Flood 0/0 $0

BRIGHT 9/6/2012 Flash Flood 0/0 $10,464

LYNCHBURG 1/30/2013 Flash Flood 0/0 $103,125

HORN LAKE DESOTO ARP 5/21/2013 Flash Flood 0/0 $1,031,246

MINERAL WELLS 7/5/2013 Flash Flood 0/0 $0

FREES CORNER 2/4/2014 Flash Flood 0/0 $0

LYNCHBURG 6/8/2014 Flash Flood 0/0 $0


STONEWALL 9/11/2014 Flash Flood 0/0 $2,029,569

LAKE CORMORANT 11/17/2015 Flash Flood 0/0 $0

LAKE CORMORANT 3/9/2016 Flash Flood 0/0 $0

NORFOLK 3/10/2016 Flood 0/0 $15,000

LOVE 3/10/2016 Flash Flood 0/0 $25,000

*Property damage is reported in 2016 dollars; all damage may not have been reported. Source: National Climatic Data Center

HISTORICAL SUMMARY OF INSURED FLOOD LOSSES According to FEMA flood insurance policy records as of June 2016, there have been 216 flood losses reported in DeSoto County through the National Flood Insurance Program (NFIP) since 1978, totaling more than $5.4 million in claims payments. A summary of these figures for the county is provided in Table B.8. It should be emphasized that these numbers include only those losses to structures that were insured through the NFIP policies, and for losses in which claims were sought and received. It is likely that many additional instances of flood loss in DeSoto County were either uninsured, denied claims payment, or not reported.



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TABLE B.8: SUMMARY OF INSURED FLOOD LOSSES IN DESOTO COUNTY

Location Number of

Policies Flood Losses Claims Payments

Hernando 27 4 $131,098

Horn Lake 200 73 $1,542,756

Olive Branch 141 19 $363,077

Southaven 356 78 $2,250,137

Walls 10 0 $0

Unincorporated Area 189 42 $1,138,498

DESOTO COUNTY TOTAL 923 216 $5,425,566

Source: National Flood Insurance Program

REPETITIVE LOSS PROPERTIES According to the Mississippi Emergency Management Agency, there are 9 non-mitigated repetitive loss properties located in DeSoto County, which accounted for 22 losses and over $670,000 in claims payments under the NFIP. The average claim amount for these properties is $30,466. Of the nine properties, seven are single family and two are non-residential. Without mitigation, these properties will likely continue to experience flood losses. Table B.9 presents detailed information on repetitive loss properties and NFIP claims and policies for DeSoto County.

TABLE B.9: REPETITIVE LOSS PROPERTIES IN DESOTO COUNTY

Location Number of Properties

Types of Properties

Number of Losses

Building Payments

Content Payments

Total Payments

Average Payment

Hernando 1 1 single

family 3 $156,702 $116,794 $273,496 $91,165

Horn Lake 1 1 non-

residential 2 $0 $26,548 $26,548 $13,274

Olive Branch 4

3 single family, 1

non-residential 9 $144,888 $30,678 $175,566 $19,507

Southaven 1 1 single

family 4 $62,133 $17,579 $79,712 $19,928

Walls 0 -- 0 $0 $0 $0 $0

Unincorporated Area 2 2 single

family 4 $91,498 $23,442 $114,939 $28,735

DESOTO COUNTY TOTAL

9 22 $455,221 $215,040 $670,261 $30,466

Source: National Flood Insurance Program

PROBABILITY OF FUTURE OCCURRENCES Flood events will remain a threat in DeSoto County, and the probability of future occurrences will remain highly likely (100 percent annual probability). The participating jurisdictions and unincorporated areas have risk to flooding, though not all areas will experience flood. The probability of future flood events based on magnitude and according to best available data is illustrated in the figure above, which indicates



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those areas susceptible to the 1-percent annual chance flood (100-year floodplain). It can be inferred from the floodplain location maps, previous occurrences, and repetitive loss properties that risk varies throughout the county. For example, the southern half of the county has more floodplain and thus a higher risk of flood than the rest of the county. Flood is not the greatest hazard of concern but will continue to occur and cause damage. Therefore, mitigation actions may be warranted, particularly for repetitive loss properties.

FIRE-RELATED HAZARDS

B.2.4 Drought

LOCATION AND SPATIAL EXTENT Drought typically covers a large area and cannot be confined to any geographic or political boundaries. Furthermore, it is assumed that DeSoto County would be uniformly exposed to drought, making the spatial extent potentially widespread. It is also notable that drought conditions typically do not cause significant damage to the built environment but may exacerbate wildfire conditions.

HISTORICAL OCCURRENCES According to the U.S. Drought Monitor, DeSoto County had drought levels of Severe or worse in 9 of the last 17 years (January 2000-June 2016). Table B.10 shows the most severe drought classification for each year, according to U.S. Drought Monitor classifications. It should be noted that the U.S. Drought Monitor also estimates what percentage of the county is in each classification of drought severity. For example, the most severe classification reported may be exceptional but a majority of the county may actually be in a less severe condition.

TABLE B.10: HISTORICAL DROUGHT OCCURRENCES IN DESOTO COUNTY Abnormally Dry (D0) Moderate Drought (D1) Severe Drought (D2) Extreme Drought (D3) Exceptional Drought (D4)

Year DeSoto County

2000 EXCEPTIONAL

2001 SEVERE

2002 ABNORMAL

2003 ABNORMAL

2004 ABNORMAL

2005 SEVERE

2006 SEVERE

2007 EXTREME

2008 ABNORMAL

2009 None

2010 SEVERE

2011 SEVERE

2012 EXTREME



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Year DeSoto County

2013 MODERATE

2014 ABNORMAL

2015 SEVERE

2016 None

Source: United States Drought Monitor (through June 2016)

Some additional anecdotal information was provided from the National Climatic Data Center on droughts in DeSoto County. Summer 2007 – Drought conditions began in early April across portions of Northeast Mississippi and expanded to North Central Mississippi by the end of April. Drought conditions continued throughout the summer months through October and at times reached exceptional conditions. The drought impacted agricultural and hydrological interests of the area. Burn bans in some locations were issued due to the lack of rainfall. Summer 2010 to Spring 2011 – Below normal rainfall from June 2010 until April 2011 resulted in drought across Northwest Mississippi. The biggest impact of the drought was on agriculture as many crops suffered due to the lack of rainfall. Many pastures were in poor condition forcing farmers to feed livestock with baled hay. Hydrological concerns started to become an issue by the end of September into March as many lake and river levels dropped. Lack of moisture in the ground also caused several pipes to burst in the region. Burn bans were issued for most of North Mississippi. Summer 2012 – Below normal rainfall fell during the month of July across North Mississippi. Many crops that were planted during the spring struggled to grow due to lack of water. Many pastures were in poor condition forcing farmers to feed cattle baled hay. Lake and river levels dropped to low levels. Burn bans were issued for many counties as a result of the dry conditions. Drought conditions improved during the month of October.

PROBABILITY OF FUTURE OCCURRENCES Based on historical occurrence information, it is assumed that DeSoto County has a probability level of likely (between 10 and 100 percent annual probability) for future drought events. However, the extent (or magnitude) of drought and the amount of geographic area covered by drought, varies with each year. Historic information indicates that there is a much lower probability for extreme, long-lasting drought conditions.

B.2.5 Lightning

LOCATION AND SPATIAL EXTENT Lightning occurs randomly, therefore it is impossible to predict where and with what frequency it will strike. It is assumed that all of DeSoto County is uniformly exposed to lightning.



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HISTORICAL OCCURRENCES According to the National Climatic Data Center, there have been seven recorded lightning events in DeSoto County since 2001.6 These events resulted in over $792,000 (2016 dollars) in damages, as listed in summary Table B.11.7 Furthermore, lightning caused seven injuries in DeSoto County. Detailed information on historical lightning events can be found in Table B.12. It is certain that more than seven events have impacted the county. Many of the reported events are those that cause damage, and it should be expected that damages are likely much higher for this hazard than what is reported.

TABLE B.11: SUMMARY OF LIGHTNING OCCURRENCES IN DESOTO COUNTY

Location Number of




Hernando 1 0/0 $1,306 $100

Horn Lake 1 0/0 $31,794 $2,650

Olive Branch 1 0/0 $1,306 $100

Southaven 3 0/7 $747,604 $49,840

Walls 1 0/0 $10,464 $2,616

Unincorporated Area 0 0/0 $0 $0

DESOTO COUNTY TOTAL

7 0/7 $792,474 $55,307


TABLE B.12: HISTORICAL LIGHTNING OCCURRENCES IN DESOTO COUNTY

Location Date Deaths/ Injuries

Property Damage*

Details

Hernando

HERNANDO 5/5/2003 0/0 $1,306 A large tree was hit by lightning and fell down.

Horn Lake

HORN LAKE 8/23/2004 0/0 $31,794 A house was badly damaged by a fire started by lightning.

Olive Branch

OLIVE BRANCH 7/13/2003 0/0 $1,306 A house was damaged by a fire set by lightning.

Southaven

SOUTH HAVEN 7/29/2001 0/6 $0 Six persons were injured when lightning struck a baseball dugout during a baseball tournament.

SOUTH HAVEN 5/1/2003 0/1 $0 A lady was injured by a lightning strike while walking to her car.

SOUTH HAVEN 6/16/2011 0/0 $747,604

Lightning struck an apartment complex in Southaven starting a fire that destroyed 8 units. A section of the roof collapsed into the structure as well.

6 These lightning events are only inclusive of those reported by the National Climatic Data Center (NCDC) from 1996 through

March 2016. It is certain that additional lightning events have occurred in DeSoto County. As additional local data becomes





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Location Date Deaths/ Injuries

Property Damage*

Details

Walls

WALLS 9/6/2012 0/0 $10,464 A lightning strike resulted in a structure fire in Walls.

Unincorporated area

None Reported -- -- -- --


PROBABILITY OF FUTURE OCCURRENCES Although there was not a high number of historical lightning events reported in DeSoto County via NCDC data, it is a regular occurrence accompanied by thunderstorms. In fact, lightning events will assuredly happen on an annual basis, though not all events will cause damage. According to Vaisala’s U.S. National Lightning Detection Network (NLDN), DeSoto County is located in an area of the country that experienced an average of 4 to 12 lightning flashes per square kilometer per year between 2005 and 2014. Therefore, the probability of future events is highly likely (100 percent annual probability). It can be expected that future lightning events will continue to threaten life and cause minor property damages throughout the county.

B.2.6 Wildfire

LOCATION AND SPATIAL EXTENT The entire county is at risk to a wildfire occurrence. However, several factors such as drought conditions or high levels of fuel on the forest floor, may make a wildfire more likely. Furthermore, areas in the urban-wildland interface are particularly susceptible to fire hazard as populations abut formerly undeveloped areas. The Wildfire Ignition Density data shown in the figure below give an indication of historic location.

HISTORICAL OCCURRENCES Figure B.4 shows the Wildfire Ignition Density in DeSoto County based on data from the Southern Wildfire Risk Assessment. This data is based on historical fire ignitions and the likelihood of a wildfire igniting in an area. Occurrence is derived by modeling historic wildfire ignition locations to create an average ignition rate map. This is measured in the number of fires per year per 1,000 acres.8

8 Southern Wildfire Risk Assessment, 2014.



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FIGURE B.4: WILDFIRE IGNITION DENSITY IN DESOTO COUNTY

Source: Southern Wildfire Risk Assessment

Based on data from the Mississippi Forestry Commission from 2012 to 2016, DeSoto County experienced an average of 1.0 wildfires annually which burned a combined 15.0 acres per year. The data indicate that these fires averaged about 15.0 acres per fire. Table B.13 provides a summary of wildfire occurrences in DeSoto County and Table B.14 lists the number of reported wildfire occurrences in the county between the years 2012 and 2016.

TABLE B.13: SUMMARY TABLE OF ANNUAL WILDFIRE OCCURRENCES (2012 -2016)* DeSoto County

Average Number of Fires per year 1.0

Average Number of Acres Burned per year 15.0

Average Number of Acres Burned per fire 15.0

*These values reflect averages over a 5-year period. Source: Mississippi Forestry Commission



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TABLE B.14: HISTORICAL WILDFIRE OCCURRENCES IN DESOTO COUNTY Year 2012 2013 2014 2015 2016

DeSoto County

Number of Fires 2 0 3 0 0

Number of Acres Burned 7 0 68 0 0

Source: Mississippi Forestry Commission

PROBABILITY OF FUTURE OCCURRENCES Wildfire events will be an ongoing occurrence in DeSoto County. Figure B.5 shows that there is some probability a wildfire will occur throughout the county. However, the likelihood of wildfires increases during drought cycles and abnormally dry conditions. Fires are likely to stay small in size but could increase due to local climate and ground conditions. Dry, windy conditions with an accumulation of forest floor fuel (potentially due to ice storms or lack of fire) could create conditions for a large fire that spreads quickly. It should also be noted that some areas do vary somewhat in risk. For example, highly developed areas are less susceptible unless they are located near the urban-wildland boundary. The risk will also vary due to assets. Areas in the urban-wildland interface will have much more property at risk, resulting in increased vulnerability and need to mitigate compared to rural, mainly forested areas. The probability assigned to DeSoto County for future wildfire events is highly likely (100 percent annual probability).



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FIGURE B.5: BURN PROBABILITY IN DESOTO COUNTY

Source: Southern Wildfire Risk Assessment

GEOLOGIC HAZARDS

B.2.7 Earthquake

LOCATION AND SPATIAL EXTENT Figure B.6 shows the intensity level associated with DeSoto County, based on the national USGS map of peak acceleration with 10 percent probability of exceedance in 50 years. It is the probability that ground motion will reach a certain level during an earthquake. The data show peak horizontal ground acceleration (the fastest measured change in speed, for a particle at ground level that is moving horizontally due to an earthquake) with a 10 percent probability of exceedance in 50 years. The map was compiled by the U.S. Geological Survey (USGS) Geologic Hazards Team, which conducts global investigations of earthquake, geomagnetic, and landslide hazards. According to this map, DeSoto County lies within an approximate zone of level “0.1” to “0.2” ground acceleration. This indicates that the county exists within an area of high seismic risk.



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FIGURE B.6: PEAK ACCELERATION WITH 10 PERCENT PROBABILITY OF EXCEEDANCE IN 50 YEARS

Source: United States Geological Survey, 2014



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It should also be noted that the State of Mississippi Hazard Mitigation Plan identifies certain areas of concern for liquefaction and lists the counties and corresponding zones within those counties that have the highest liquefaction potential. The zones of high risk for DeSoto County can be found in Table B.15.

TABLE B.15: HIGH LIQUEFACTION HAZARD FOR DESOTO COUNTY

County Seismic Source* Geographic Area of

Concern Liquefaction Potential

by Seismic Zone

DeSoto County NMSZ, WRFZ Mississippi River

Floodplain, Coldwater River Floodplain

Very High, Very Low

*NMSZ = New Madrid Seismic Zone; WRFZ = White River Fault Zone Source: State of Mississippi Standard Mitigation Plan (2013 Update)

HISTORICAL OCCURRENCES At least 22 earthquakes are known to have affected DeSoto County since 1931. The strongest of these measured a V on the Modified Mercalli Intensity (MMI) scale. Table B.16 provides a summary of earthquake events reported by the National Geophysical Data Center between 1638 and 1985. Table B.17 presents a detailed occurrence of each event including the date, distance for the epicenter, magnitude and Modified Mercalli Intensity (if known). 9

TABLE B.16: SUMMARY OF SEISMIC ACTIVITY IN DESOTO COUNTY

Location Number of

Occurrences Greatest MMI

Reported Greatest Richter Scale

Reported

Hernando 7 V 5.3

Horn Lake 3 IV 4.9

Olive Branch 2 V 4.9

Southaven 0 -- --

Walls 3 V 4.9

Unincorporated Area 7 V 4.9

DESOTO COUNTY TOTAL 22 V (slightly strong) 5.3

Source: National Geophysical Data Center

TABLE B.17: SIGNIFICANT SEISMIC EVENTS IN DESOTO COUNTY (1638 -1985) Location Date Epicentral Distance Magnitude MMI

Hernando

Hernando 12/17/1931 81.0 km Unknown V

Hernando 12/16/1947 Unknown Unknown III

Hernando 1/25/1955 91.0 km Unknown III

Hernando 6/4/1967 159.0 km 3.8 IV

Hernando 11/9/1968 377.0 km 5.3 IV

Hernando 11/17/1970 120.0 km 3.6 IV

Hernando 3/25/1976 96.0 km 4.9 V

9 Due to reporting mechanisms, not all earthquakes events were recorded during this time. Furthermore, some are missing data,

such as the epicenter location, due to a lack of widely used technology. In these instances, a value of “unknown” is reported.



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Location Date Epicentral Distance Magnitude MMI

Horn Lake

Horn Lake 3/3/1963 193.0 km 4.5 III

Horn Lake 3/29/1972 143.0 km 3.7 III

Horn Lake 3/25/1976 81.0 km 4.9 IV

Olive Branch

Olive Branch 11/17/1970 104.0 km 3.6 III

Olive Branch 3/25/1976 92.0 km 4.9 V

Southaven


Walls

Walls 3/3/1963 193.0 km 4.5 III

Walls 11/17/1970 106.0 km 3.6 IV

Walls 3/25/1976 76.0 km 4.9 V

Unincorporated Area

Lake Cormorant 12/17/1931 96.0 km Unknown IV

Lake Cormorant 3/3/1963 200.0 km 4.5 III

Lake Cormorant 6/4/1967 157.0 km 3.8 IV

Mineral Wells 3/29/1972 136.0 km 3.7 IV

Lake Cormorant 3/25/1976 80.0 km 4.9 V

Mineral Wells 3/25/1976 87.0 km 4.9 V

Nesbit 3/25/1976 89.0 km 4.9 V

Source: National Geophysical Data Center

PROBABILITY OF FUTURE OCCURRENCES The probability of significant, damaging earthquake events affecting DeSoto County is unlikely. However, it is certainly possible that future earthquakes resulting in light or moderate perceived shaking and damages will affect the county much more frequently. The annual probability level for the county is estimated to be between 10 and 100 percent (likely).

B.2.8 Landslide

LOCATION AND SPATIAL EXTENT Landslides occur along steep slopes when the pull of gravity can no longer be resisted (often due to heavy rain). Human development can also exacerbate risk by building on previously undevelopable steep slopes. Landslides are possible throughout DeSoto County, though the risk is relatively low. According to Figure B.7 below, approximately half of the county falls under a low incidence area, indicating that in these zones less than 1.5 percent of the area is involved in landsliding. The other half has moderate incidence, indicating that between 1.5 and 15 percent of the area is involved in landsliding. There are also areas in the northwestern corner and center of the county that have high susceptibility, indicating that there is a somewhat higher potential for landslides to occur in these area.



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FIGURE B.7: LANDSLIDE SUSCEPTIBILITY AND INCIDENCE MAP OF DESOTO COUNTY

Source: United States Geological Survey

HISTORICAL OCCURRENCES There is no extensive history of landslides in DeSoto County. Landslide events typically occur in isolated areas, but no major landslide events were reported.

PROBABILITY OF FUTURE OCCURRENCES Based on historical information and the USGS susceptibility index, the probability of future landslide events is possible (between 1 and 10 percent annual probability). The USGS data indicates that half of the areas in DeSoto County have a low incidence rate and some areas also have low susceptibly to landsliding activity. There are areas in the northwestern corner and center of the county that have high susceptibility. Local conditions may become more favorable for landslides due to heavy rain, for example. This would increase the likelihood of occurrence. It should also be noted that some areas in DeSoto County have greater risk than others given factors such as steepness on slope and modification of slopes.



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B.2.9 Land Subsidence/Sinkhole

LOCATION AND SPATIAL EXTENT According to the U.S. Geological Survey (USGS), subsidence affects an estimated 17,000 square miles in 45 states, including Mississippi. Salt and gypsum underlie about 35 to 40 percent of the United States, though in many areas they are buried at great depths. Figure B.8 shows the location of rock types associated with subsidence in the United States. It indicates that there may be areas in DeSoto County underlain with soil and rock types that are susceptible to land subsidence, but overall the northwest part of the state is not underlain by these soil/rock types.

FIGURE B.8: MAP OF ROCK TYPES ASSOCIATED WITH SUBSIDENCE IN THE UNITED STATES

Source: United States Geological Survey

HISTORICAL OCCURRENCES Although there is no extensive recorded history of land subsidence in DeSoto County, anecdotal evidence of isolated incidents have been reported. Local county officials have noted the impacts from these swings and changes in soil as roads and other infrastructure have experienced large cracks and breaks, causing stops in daily operations and significant costs to local, state, and federal budgets. Often the cost to repair this infrastructure can be in the range of millions of dollars depending on the degree of damage and necessity for quick repairs.

PROBABILITY OF FUTURE OCCURRENCES The probability of future land subsidence events in the county is possible (between 1 and 10 percent annual probability). The potential for land subsidence may be impacted by local conditions such as heavy rain or extremely dry periods.



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WIND-RELATED HAZARDS

B.2.10 Extreme Heat

LOCATION AND SPATIAL EXTENT Heat waves typically impact a large area and cannot be confined to any geographic or political boundaries. Therefore the entire county is considered to be equally susceptible to extreme heat.

HISTORICAL OCCURRENCES The National Climatic Data Center was used to determine historical heat wave occurrences in the county. August 2007 – During the first half of August, a heat wave took hold of the region and brought some of the warmest temperatures since the summer of 2000. This heat wave began around August 5th and lasted until the 16th. Between August 10th and 15th, the entire area reached 100 degrees or higher. Twenty three record highs were also set during this time. As the temperature soared each day, high relative humidities resulted in heat index values between 105 and 112 degrees. July to August 2010 – High pressure was firmly entrenched across the southeast and allowed temperatures to soar into the triple digits across much of the region numerous times during the months of July and August. Additionally, relatively high humidity levels made conditions even more oppressive, with heat index readings surpassing 110 degrees in many areas. July to August 2011 – A strong upper ridge of high pressure moved over the Mid-South during the middle part of July and beginning of August. As a result, high temperatures ranged in the mid-90s to low 100s. Dew points ranged from the lower to upper 70s. The combination of the hot and humid conditions allowed heat indices to reach between 110 and 120 degrees during the afternoon hours. July 2012 – An upper ridge of high pressure moved back over the Mid-South during the middle part of July. Temperatures rose into low 100s during the afternoon hours of July 19th-July 20th, 2012. The combination of heat and humidity produced heat indices above 110 degrees.

PROBABILITY OF FUTURE OCCURRENCES Based on historical occurrence information, it is assumed that all of DeSoto County has a probability level of likely (between 10 and 100 percent annual probability) for future heat wave events.

B.2.11 Hailstorm

LOCATION AND SPATIAL EXTENT Hailstorms frequently accompany thunderstorms, so their locations and spatial extents coincide. It is assumed that DeSoto County is uniformly exposed to severe thunderstorms; therefore, all areas of the county are equally exposed to hail which may be produced by such storms. With that in mind, Figure B.9 shows the location of hail events that have impacted the county between 1955 and 2015.



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FIGURE B.9: HAILSTORM TRACKS IN DESOTO COUNTY

Source: National Weather Service Storm Prediction Center

HISTORICAL OCCURRENCES According to the National Climatic Data Center, 129 recorded hailstorm events have affected DeSoto County since 1962.10 Table B.18 is a summary of the hail events in DeSoto County. Table B.19 provides detailed information about each event that occurred in the county. In all, hail occurrences resulted in approximately $154,000 (2016 dollars) in property damages.11 Hail ranged in diameter from 0.75 inches to 2.0 inches. It should be noted that hail is notorious for causing substantial damage to cars, roofs, and other areas of the built environment that may not be reported to the National Climatic Data Center. Therefore, it is likely that damages are greater than the reported value.

10 These hail events are only inclusive of those reported by the National Climatic Data Center (NCDC) from 1955 through March

2016. It is likely that additional hail events have affected DeSoto County. As additional local data becomes available, this hazard

profile will be amended. 11 Adjusted dollar values were calculated based on the average Consumer Price Index for a given calendar year. This index value




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TABLE B.18: SUMMARY OF HAIL OCCURRENCES IN DESOTO COUNTY

Location Number of




Hernando 29 0/0 $28,945 $1,316

Horn Lake 9 0/0 $46,706 $2,123

Olive Branch 18 0/0 $20,842 $1,303

Southaven 14 0/0 $17,267 $785

Walls 6 0/0 $2,210 $130

Unincorporated Area 53 0/0 $37,796 $700

DESOTO COUNTY TOTAL

129 0/0 $153,766 $6,356


TABLE B.19: HISTORICAL HAIL OCCURRENCES IN DESOTO COUNTY Location Date Magnitude Deaths/Injuries Property Damage*

Hernando

Hernando 4/26/1994 1.75 in. 0/0 $811

Hernando 4/26/1994 0.75 in. 0/0 $81

Hernando 3/20/1995 0.75 in. 0/0 $158

Hernando 5/15/1995 1.75 in. 0/0 $7,882

Hernando 7/9/1995 0.75 in. 0/0 $158

HERNANDO 1/4/1997 0.75 in. 0/0 $15

HERNANDO 4/27/1998 0.75 in. 0/0 $15

HERNANDO 3/31/2001 1.00 in. 0/0 $136

HERNANDO 3/31/2001 0.75 in. 0/0 $14

HERNANDO 5/20/2001 1.75 in. 0/0 $1,017

HERNANDO 5/27/2001 0.75 in. 0/0 $14

HERNANDO 10/24/2001 0.75 in. 0/0 $14

HERNANDO 10/24/2001 0.75 in. 0/0 $14

HERNANDO 11/24/2001 1.00 in. 0/0 $136

HERNANDO 11/15/2005 2.00 in. 0/0 $1,304

HERNANDO 4/2/2006 0.88 in. 0/0 $4,171

HERNANDO 5/3/2006 0.75 in. 0/0 $1,192

HERNANDO 4/3/2007 1.75 in. 0/0 $2,317

HERNANDO 4/13/2007 1.00 in. 0/0 $2,317

HERNANDO 3/15/2008 1.00 in. 0/0 $2,232

HERNANDO 3/15/2008 0.75 in. 0/0 $1,116

HERNANDO 3/15/2008 0.75 in. 0/0 $1,116

HERNANDO 4/22/2008 0.88 in. 0/0 $1,674

HERNANDO 4/24/2010 0.75 in. 0/0 $0

HERNANDO 4/24/2010 0.75 in. 0/0 $0

HERNANDO 5/25/2011 1.00 in. 0/0 $0

HERNANDO 1/22/2012 1.00 in. 0/0 $1,046

HERNANDO 4/27/2014 1.00 in. 0/0 $0

HERNANDO 3/31/2016 1.00 in. 0/0 $0



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Location Date Magnitude Deaths/Injuries Property Damage*

Horn Lake

Horn Lake 4/26/1994 1.75 in. 0/0 $811

HORN LAKE 4/24/2002 0.88 in. 0/0 $67

HORN LAKE 7/18/2003 0.88 in. 0/0 $131

HORN LAKE 4/7/2006 1.25 in. 0/0 $23,833

HORN LAKE 4/7/2006 1.00 in. 0/0 $17,875

HORN LAKE 4/3/2007 0.88 in. 0/0 $1,159

HORN LAKE 4/13/2007 1.00 in. 0/0 $1,159

HORN LAKE 5/22/2008 0.88 in. 0/0 $1,674

HORN LAKE 6/16/2011 1.00 in. 0/0 $0

Olive Branch

OLIVE BRANCH 2/13/2000 0.75 in. 0/0 $1,395

OLIVE BRANCH 2/13/2000 0.75 in. 0/0 $14

OLIVE BRANCH 4/30/2002 0.75 in. 0/0 $13

OLIVE BRANCH 5/6/2003 1.00 in. 0/0 $6,528

OLIVE BRANCH 7/13/2003 0.88 in. 0/0 $78

OLIVE BRANCH 3/20/2004 1.00 in. 0/0 $127

OLIVE BRANCH 3/20/2004 1.00 in. 0/0 $153

OLIVE BRANCH 7/14/2004 1.75 in. 0/0 $1,081

OLIVE BRANCH 6/10/2005 1.00 in. 0/0 $123

OLIVE BRANCH 4/3/2007 1.75 in. 0/0 $2,317

OLIVE BRANCH 8/2/2007 1.00 in. 0/0 $2,317

OLIVE BRANCH 3/14/2008 1.75 in. 0/0 $5,579

OLIVE BRANCH 3/14/2008 0.75 in. 0/0 $1,116

OLIVE BRANCH 6/12/2009 1.00 in. 0/0 $0

OLIVE BRANCH 6/12/2009 1.00 in. 0/0 $0

OLIVE BRANCH 4/19/2011 1.00 in. 0/0 $0

OLIVE BRANCH 6/16/2011 1.00 in. 0/0 $0

OLIVE BRANCH 6/22/2014 1.00 in. 0/0 $0

Southaven Southaven 3/24/1994 0.75 in. 0/0 $0

Southaven 4/26/1994 1.75 in. 0/0 $811

Southaven 3/20/1995 0.88 in. 0/0 $315

Southaven 3/20/1995 0.75 in. 0/0 $158

SOUTH HAVEN 2/18/2000 0.75 in. 0/0 $14

SOUTH HAVEN 4/7/2000 0.75 in. 0/0 $14

SOUTH HAVEN 5/20/2001 1.75 in. 0/0 $1,017

SOUTH HAVEN 12/18/2002 0.75 in. 0/0 $13

SOUTH HAVEN 7/7/2004 1.75 in. 0/0 $967

SOUTH HAVEN 4/22/2005 0.75 in. 0/0 $12

SOUTH HAVEN 11/6/2005 1.00 in. 0/0 $135

SOUTH HAVEN 3/15/2008 0.75 in. 0/0 $1,116

SOUTH HAVEN 5/2/2008 1.00 in. 0/0 $2,232

SOUTH HAVEN 1/22/2012 1.75 in. 0/0 $10,464

Walls WALLS 5/4/1999 1.75 in. 0/0 $1,081



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WALLS 11/6/2005 0.75 in. 0/0 $12

WALLS TWINKLE TOWN F 5/10/2008 0.75 in. 0/0 $1,116

WALLS 4/24/2010 1.00 in. 0/0 $0

WALLS 4/25/2011 0.88 in. 0/0 $0

WALLS 6/13/2011 1.50 in. 0/0 $0

Unincorporated Area

DE SOTO CO. 3/31/1962 2.00 in. 0/0 $0

DE SOTO CO. 2/18/1976 1.00 in. 0/0 $0

DE SOTO CO. 4/30/1985 1.75 in. 0/0 $0

DE SOTO CO. 4/30/1985 1.75 in. 0/0 $0

DE SOTO CO. 4/30/1985 1.75 in. 0/0 $0

DE SOTO CO. 4/30/1985 0.75 in. 0/0 $0

DE SOTO CO. 7/31/1986 1.75 in. 0/0 $0

DE SOTO CO. 4/11/1987 1.75 in. 0/0 $0

DE SOTO CO. 8/14/1987 1.75 in. 0/0 $0

DE SOTO CO. 3/30/1989 0.75 in. 0/0 $0

DE SOTO CO. 6/3/1989 0.75 in. 0/0 $0

DE SOTO CO. 6/11/1989 0.75 in. 0/0 $0

Midway 8/2/1993 0.75 in. 0/0 $0

Byhalia 4/26/1994 1.00 in. 0/0 $811

Nesbit 4/26/1994 1.75 in. 0/0 $811

Penton 5/18/1995 1.00 in. 0/0 $1,576

NESBIT 4/27/1998 0.75 in. 0/0 $15

LEWISBURG 4/27/1998 0.75 in. 0/0 $15

LEWISBURG 5/28/1998 1.75 in. 0/0 $1,105

LEWISBURG 5/20/2001 1.00 in. 0/0 $136

LAKE CORMORANT 10/24/2001 0.75 in. 0/0 $14

PLEASANT HILL 11/24/2001 0.88 in. 0/0 $68

LEWISBURG 5/5/2003 0.75 in. 0/0 $13


EUDORA 7/18/2003 1.00 in. 0/0 $196

LEWISBURG 12/3/2005 0.88 in. 0/0 $62

EUDORA 1/13/2006 1.00 in. 0/0 $119

EUDORA 4/2/2006 1.25 in. 0/0 $7,150

EUDORA 5/10/2006 0.88 in. 0/0 $2,979

LEWISBURG 4/13/2007 0.75 in. 0/0 $1,159

DAYS 4/13/2007 0.75 in. 0/0 $1,159

FREES CORNER 3/15/2008 1.75 in. 0/0 $5,579

EUDORA 3/15/2008 0.75 in. 0/0 $1,116

NESBIT 3/15/2008 1.00 in. 0/0 $2,232

LEWISBURG 3/15/2008 0.75 in. 0/0 $1,116

BRIGHT 5/2/2008 0.88 in. 0/0 $1,674

HANDY CORNER 5/10/2008 0.88 in. 0/0 $1,674

LOVE 7/5/2008 0.75 in. 0/0 $1,116

BRIGHT 7/5/2008 1.75 in. 0/0 $5,579

CEDARVIEW 6/12/2009 0.88 in. 0/0 $0



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EUDORA 4/24/2010 0.75 in. 0/0 $0


HORN LAKE DESOTO ARP 4/24/2010 1.75 in. 0/0 $0

PLEASANT HILL 4/24/2010 1.75 in. 0/0 $0

LOVE 4/19/2011 0.75 in. 0/0 $0

LOVE 4/26/2011 0.88 in. 0/0 $0

LEWISBURG 5/13/2011 1.00 in. 0/0 $0

MILLER 6/16/2011 0.88 in. 0/0 $0

MILLER 2/1/2012 0.88 in. 0/0 $0

HORN LAKE DESOTO ARP 7/7/2012 1.00 in. 0/0 $0

LEWISBURG 10/17/2012 1.00 in. 0/0 $0

MINERAL WELLS 6/27/2013 1.00 in. 0/0 $0

PLUM PT 10/2/2014 1.00 in. 0/0 $0


PROBABILITY OF FUTURE OCCURRENCES Based on historical occurrence information, it is assumed that the probability of future hail occurrences is highly likely (100 percent annual probability). Since hail is an atmospheric hazard, it is assumed that DeSoto County has equal exposure to this hazard. It can be expected that future hail events will continue to cause minor damage to property and vehicles throughout the county.

B.2.12 Hurricane and Tropical Storm

LOCATION AND SPATIAL EXTENT Hurricanes and tropical storms threaten the entire Atlantic and Gulf seaboard of the United States. While coastal areas are most directly exposed to the brunt of landfalling storms, their impact is often felt hundreds of miles inland and they can affect DeSoto County. All areas in DeSoto County are equally susceptible to hurricane and tropical storms.

HISTORICAL OCCURRENCES According to the National Hurricane Center’s historical storm track records, 36 hurricane or tropical storm/depression tracks have passed within 75 miles of the MEMA District 1 Region since 1860.12 This includes: 1 Category 1 hurricane, 17 tropical storms, and 18 tropical depressions. A total of 20 tracks passed directly through the region as shown in Figure B.10. These events were all tropical storm or tropical depression strength at the time they traversed the region. Table B.20 provides the date of occurrence, name (if applicable), maximum wind speed (as recorded within 75 miles of the MEMA District 1 Region) and category of the storm based on the Saffir-Simpson Scale for each event.

12 These storm track statistics include tropical depressions, tropical storms, and hurricanes. Lesser events may still cause

significant local impact in terms of rainfall and high winds.



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FIGURE B.10: HISTORICAL HURRICANE STORM TRACKS WITHIN 75 MILES OF THE MEMA DISTRICT 1 REGION

Source: National Oceanic and Atmospheric Administration; National Hurricane Center

TABLE B.20: HISTORICAL STORM TRACKS WITHIN 75 MILES OF THE MEMA 1 DISTRICT REGION

(1850–2015)

Date of Occurrence Storm Name Maximum Wind

Speed (knots) Storm Category

10/3/1860 UNNAMED 50 Tropical Storm

9/17/1862 NOT NAMED -- Tropical Depression

10/7/1879 NOT NAMED -- Tropical Depression





9/21/1898 UNNAMED 30 Tropical Depression






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Date of Occurrence Storm Name Maximum Wind

Speed (knots) Storm Category














9/9/1950 EASY 20 Tropical Depression

6/28/1957 AUDREY 40 Tropical Storm

9/11/1965 BETSY 30 Tropical Depression

8/18/1969 CAMILLE 75 Category 1

7/12/1979 BOB 30 Tropical Depression

8/16/1985 DANNY 30 Tropical Depression

8/4/1995 ERIN 20 Tropical Depression

8/7/2001 BARRY 15 Tropical Depression

10/4/2002 LILI 30 Tropical Depression

7/11/2005 DENNIS 25 Tropical Depression

8/29/2005 KATRINA 50 Tropical Storm

8/30/2012 ISAAC 35 Tropical Storm

Source: National Hurricane Center

Federal records indicate that one disaster declaration was made in 2005 (Hurricane Katrina) in DeSoto County.13 Hurricane and tropical storm events can cause substantial damage in the area due to high winds and flooding. The National Climatic Data Center also reported one hurricane or tropical storm event in DeSoto County since 2005.14 This storm is listed in Table B.21 and is generally representative of storms with the greatest impact on the county over that time period.

TABLE B.21: HISTORICAL HURRICANE/TROPICAL STORM OCCURRENCES IN DESOTO COUNTY Date of

Occurrence Storm Name Deaths/Injuries

Property Damage (2016)15


8/30/2005 Hurricane Katrina 0/0 $12,301 $1,118


13 A complete listing of historical disaster declarations can be found in Section 4: Hazard Identification. 14 These hurricane events are only inclusive of those reported by the National Climatic Data Center (NCDC) from 1996 through

March 2016. It is likely that additional occurrences have occurred and have gone unreported. 15 Adjusted dollar values were calculated based on the average Consumer Price Index for a given calendar year. This index value




B:33

Flooding and high winds from hurricanes and tropical storms can cause damage throughout the county. Anecdotes are available from NCDC for the major storms that have impacted the county as found below: Hurricane Katrina – August 29, 2005 Hurricane Katrina had weakened to tropical storm strength when it reached north Mississippi. Numerous trees and power lines along with some telephone poles were blown down. Some trees fell on cars, mobile homes and apartment buildings. Four to eight inches of rain fell in some parts of northeast Mississippi producing some flash flooding. Overall at least 100,000 customers lost power.

PROBABILITY OF FUTURE OCCURRENCES Given the inland location of the county, it is more likely to be affected by remnants of hurricane and tropical storm systems (as opposed to a major hurricane) which may result in flooding or high winds. The probability of being impacted is less than coastal areas, but still remains a real threat to DeSoto County due to induced events like flooding. Based on historical evidence, the probability level of future occurrence is possible (between 1 and 10 percent annual probability). Given the regional nature of the hazard, all areas in the county are equally exposed to this hazard. However, when the county is impacted, the damage could be catastrophic, threatening lives and property throughout the planning area.

B.2.13 Severe Thunderstorm/High Wind

LOCATION AND SPATIAL EXTENT A thunderstorm event is an atmospheric hazard, and thus has no geographic boundaries. It is typically a widespread event that can occur in all regions of the United States. However, thunderstorms are most common in the central and southern states because atmospheric conditions in those regions are favorable for generating these powerful storms. It is assumed that DeSoto County has uniform exposure to an event and the spatial extent of an impact could be large. With that in mind, Figure B.11 shows the location of wind events that have impacted the county between 1955 and 2015.



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FIGURE B.11: SEVERE THUNDERSTORM TRACKS IN DESOTO COUNTY


HISTORICAL OCCURRENCES Severe storms were at least partially responsible for two disaster declarations in Desoto County in 2001 and 2011.16 According to NCDC, there have been 142 reported thunderstorm and high wind events since 1961 in DeSoto County.17 These events caused more than $10.4 million (2016 dollars) in damages.18 There were also reports of one fatality and one injury. Table B.22 summarizes this information. Table B.23 presents detailed thunderstorm and high wind event reports including date, magnitude, and associated damages for each event.

16 A complete listing of historical disaster declarations can be found in Section 4: Hazard Identification. 17 These thunderstorm events are only inclusive of those reported by the National Climatic Data Center (NCDC) from 1955

through March 2016 and these high wind events are only inclusive of those reported by NCDC from 1996 through March 2016. It

is likely that additional thunderstorm and high wind events have occurred in DeSoto County. As additional local data becomes





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TABLE B.22: SUMMARY OF THUNDERSTORM/HIGH WIND OCCURRENCES IN DESOTO COUNTY

Location Number of




Hernando 13 0/0 $91,634 $4,582

Horn Lake 9 0/0 $104,277 $4,534

Olive Branch 22 0/1 $3,512,459 $159,657

Southaven 11 0/0 $95,014 $4,751

Walls 9 0/0 $45,477 $2,274

Unincorporated Area 78 1/0 $6,588,686 $119,794

DESOTO COUNTY TOTAL

142 1/1 $10,437,547 $295,592


TABLE B.23: HISTORICAL THUNDERSTORM/HIGH WIND OCCURRENCES IN DESOTO COUNTY

Location Date Type Magnitude† Deaths/Injuries Property Damage*

Hernando

HERNANDO 11/7/1996 Thunderstorm Wind -- 0/0 $7,656






HERNANDO 5/30/2004 Thunderstorm Wind 55 kts. EG 0/0 $1,272






HERNANDO 6/12/2009 Thunderstorm Wind 61 kts. EG 0/0 $0

Horn Lake

Horn Lake 8/5/1993 Thunderstorm Wind 0 kts. 0/0 $831

Horn Lake 11/5/1994 Thunderstorm Wind 0 kts. 0/0 $81,051

Horn Lake 10/27/1995 Thunderstorm Wind 0 kts. 0/0 $7,882

HORN LAKE 8/24/2002 Thunderstorm Wind -- 0/0 $13,354

HORN LAKE 8/18/2007 Thunderstorm Wind 50 kts. EG 0/0 $1,159

HORN LAKE 5/6/2009 Thunderstorm Wind 50 kts. EG 0/0 $0




Olive Branch

Olive Branch 6/9/1994 Thunderstorm Wind 53 kts. 0/0 $811

OLIVE BRANCH 6/27/1997 Thunderstorm Wind -- 0/0 $14,968


OLIVE BRANCH 5/21/2001 Thunderstorm Wind 80 kts. E 0/0 $135,650




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OLIVE BRANCH 3/20/2004 Thunderstorm Wind 55 kts. EG 0/0 $12,718








OLIVE BRANCH 6/12/2009 Thunderstorm Wind 61 kts. EG 0/0 $0


OLIVE BRANCH 6/12/2009 Thunderstorm Wind 68 kts. MG 0/0 $0


OLIVE BRANCH 6/13/2011 Thunderstorm Wind 83 kts. EG 0/1 $3,204,015


OLIVE BRANCH ARPT 7/30/2012 Thunderstorm Wind 56 kts. MG 0/0 $0


Southaven

SOUTH HAVEN 1/18/1996 Thunderstorm Wind -- 0/0 $15,311






SOUTH HAVEN 8/23/2003 Thunderstorm Wind 50 kts. EG 0/0 $1,306




SOUTH HAVEN 9/6/2012 Thunderstorm Wind 50 kts. EG 0/0 $0

Walls

WALLS 11/7/1996 Thunderstorm Wind -- 0/0 $1,531




WALLS 11/6/2005 Thunderstorm Wind 65 kts. EG 0/0 $1,230

WALLS 5/10/2008 Thunderstorm Wind 61 kts. EG 0/0 $0

WALLS 7/31/2008 Thunderstorm Wind 50 kts. EG 0/0 $2,232



Unincorporated Area

DE SOTO CO. 4/25/1961 Thunderstorm Wind 0 kts. 0/0 $0







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Lake Cormorant 5/18/1993 Thunderstorm Wind 0 kts. 0/0 $831

Nesbit 8/5/1993 Thunderstorm Wind 0 kts. 0/0 $8,313

N Portion 9/24/1993 Thunderstorm Wind 0 kts. 0/0 $831

INGRAMS MILL 2/27/1996 Thunderstorm Wind -- 0/0 $76,557

PLEASANT HILL 5/28/1996 Thunderstorm Wind -- 0/0 $3,062

PENTON 6/17/1997 Thunderstorm Wind -- 0/0 $1,497

COUNTYWIDE 6/5/1998 Thunderstorm Wind 65 kts. 0/0 $3,684,601

STONEWALL 11/24/2001 Thunderstorm Wind -- 0/0 $20,347

CEDARVIEW 11/26/2001 Thunderstorm Wind -- 0/0 $27,130

DE SOTO (ZONE) 9/26/2002 High Wind 35 kts. E 0/0 $13,354

COCKRUM 6/11/2003 Thunderstorm Wind 60 kts. EG 0/0 $26,113

COUNTYWIDE 7/22/2003 Thunderstorm Wind 70 kts. EG 0/0 $2,219,572

EUDORA 8/23/2003 Thunderstorm Wind 50 kts. EG 0/0 $1,306

EUDORA 7/4/2004 Thunderstorm Wind 50 kts. EG 1/0 $12,718

COCKRUM 6/9/2005 Thunderstorm Wind 50 kts. EG 0/0 $1,230

DE SOTO (ZONE) 10/16/2006 Strong Wind 40 kts. EG 0/0 $1,192


DE SOTO (ZONE) 1/29/2008 High Wind 50 kts. EG 0/0 $18,969

LAKE CORMORANT 3/15/2008 Thunderstorm Wind 50 kts. EG 0/0 $2,232



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FREES CORNER 3/15/2008 Thunderstorm Wind 50 kts. EG 0/0 $1,116

CUB LAKE 5/2/2008 Thunderstorm Wind 50 kts. EG 0/0 $2,232

BRIGHT 5/2/2008 Thunderstorm Wind 50 kts. EG 0/0 $2,232

HANDY CORNER 5/10/2008 Thunderstorm Wind 63 kts. MG 0/0 $0

COCKRUM 5/24/2008 Thunderstorm Wind 60 kts. EG 0/0 $0

MINERAL WELLS 6/12/2008 Thunderstorm Wind 50 kts. EG 0/0 $11,158

MILLER 7/22/2008 Thunderstorm Wind 50 kts. EG 0/0 $4,463

LAKE CORMORANT 7/31/2008 Thunderstorm Wind 50 kts. EG 0/0 $2,232


LAKE CORMORANT 5/6/2009 Thunderstorm Wind 50 kts. EG 0/0 $0

LEWISBURG 5/27/2009 Thunderstorm Wind 50 kts. EG 0/0 $0

NESBIT 6/11/2009 Thunderstorm Wind 50 kts. EG 0/0 $0

EUDORA 6/12/2009 Thunderstorm Wind 50 kts. EG 0/0 $0

ALDENS 6/12/2009 Thunderstorm Wind 52 kts. EG 0/0 $0

DAYS 6/14/2009 Thunderstorm Wind 50 kts. EG 0/0 $0

COCKRUM 6/14/2009 Thunderstorm Wind 50 kts. EG 0/0 $0

MILLER 7/13/2009 Thunderstorm Wind 52 kts. EG 0/0 $0


INGRAMS MILL 4/15/2011 Thunderstorm Wind 61 kts. EG 0/0 $0

LOVE 4/19/2011 Thunderstorm Wind 61 kts. EG 0/0 $0

HORN LAKE DESOTO ARP 4/25/2011 Thunderstorm Wind 50 kts. EG 0/0 $1,068

PLEASANT HILL 8/12/2011 Thunderstorm Wind 50 kts. EG 0/0 $0

LOVE 10/17/2012 Thunderstorm Wind 50 kts. EG 0/0 $418,541


MARIENETTE 2/20/2014 Thunderstorm Wind 50 kts. EG 0/0 $0

PLEASANT HILL 4/4/2014 Thunderstorm Wind 56 kts. EG 0/0 $0

NESBIT 10/2/2014 Thunderstorm Wind 55 kts. MG 0/0 $0

*Property damage is reported in 2016 dollars; all damage may not have been reported. †E = estimated; EG = estimated gust; ES = estimated sustained; MG = measured gust; MS = measured sustained Source: National Climatic Data Center

PROBABILITY OF FUTURE OCCURRENCES Given the high number of previous events, it is certain that thunderstorm events, including straight-line wind events, will occur in the future. This results in a probability level of highly likely (100 percent annual probability) for the entire county.

B.2.14 Tornado

LOCATION AND SPATIAL EXTENT Tornadoes occur throughout the state of Mississippi, and thus in DeSoto County. Tornadoes typically impact a relatively small area, but damage may be extensive. Event locations are completely random and it is not possible to predict specific areas that are more susceptible to tornado strikes over time. Therefore, it is assumed that DeSoto County is uniformly exposed to this hazard. With that in mind, Figure B.12 shows



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tornado track data for many of the major tornado events that have impacted the county between 1950 and 2015. While no definitive pattern emerges from this data, some areas that have been impacted in the past may be potentially more susceptible in the future.

FIGURE B.12: HISTORICAL TORNADO TRACKS IN DESOTO COUNTY


HISTORICAL OCCURRENCES Tornadoes were at least partially responsible for three disaster declarations in DeSoto County in 1973, 2001, and 2011.19 According to the National Climatic Data Center, there have been a total of 24 recorded tornado events in DeSoto County since 1962 (Table B.24), resulting in almost $59.5 million (2016 dollars) in property damages.20 21 In addition, 1 fatality and 105 injuries were reported. The magnitude of these tornadoes ranges from F0 to F3 and EF0 to EF2 in intensity, although an EF5 event is possible. Detailed information on historic tornado events can be found in Table B.25.

19 A complete listing of historical disaster declarations can be found in Section 4: Hazard Identification. 20 These tornado events are only inclusive of those reported by the National Climatic Data Center (NCDC) from 1950 through

March 2016. It is likely that additional tornadoes have occurred in DeSoto County. As additional local data becomes available,

this hazard profile will be amended. 21 Adjusted dollar values were calculated based on the average Consumer Price Index for a given calendar year. This index value




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TABLE B.24: SUMMARY OF TORNADO OCCURRENCES IN DESOTO COUNTY

Location Number of




Hernando 1 0/0 $811 $37

Horn Lake 2 0/0 $80,205 $3,646

Olive Branch 3 0/2 $4,725,170 $429,561

Southaven 0 0/0 $0 $0

Walls 0 0/0 $0 $0

Unincorporated Area 18 1/103 $54,663,585 $1,012,289

DESOTO COUNTY TOTAL

24 1/105 $59,469,771 $1,445,532


TABLE B.25: HISTORICAL TORNADO IMPACTS IN DESOTO COUNTY

Location Date Magnitude Deaths/ Injuries

Property Damage*

Details

Hernando

Hernando 4/26/1994 F0 0/0 $811 A tornado briefly touched down just northeast of Hernando. Some trees were blown down.

Horn Lake

Horn Lake 4/26/1994 F0 0/0 $8,105

A tornado touched down in the northern part of DeSoto County. Several tree tops were ripped off.

HORN LAKE 1/22/1999 F0 0/0 $72,100

A tornado touched down in Horn Lake. Five homes suffered serious structural damage while 100 other homes had lesser damage.

Olive Branch

OLIVE BRANCH 3/22/2005 F0 0/0 $61,504

The tornado touched down on the southwest edge of the Cherokee Valley Golf Course and moved northeast. A car wash and a Jiffy Lube had the glass blown out of their buildings. A large oak tree at the golf course was uprooted. Some shingles and small trees were blown down.

OLIVE BRANCH 3/22/2005 F1 0/1 $184,513

The tornado touched down in the Alexandria Ridge subdivision in Olive Branch and moved northeast. One home suffered extensive roof damage. Another home had an air conditioner blown through one of the windows. Several other homes suffered minor shingle and fence damage.



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Property Damage*

Details

OLIVE BRANCH 6/12/2009 EF2 0/1 $4,479,153

A tornado touched down at the truck weighing scales on Highway 78 about 1 mile southeast of Goodman Road in Olive Branch. The tornado had a non-continuous track to the east-northeast for 2.9 miles and ended a few hundred yards east of Hacks Cross Road about one half mile south of Goodman Road. The maximum estimated winds were 125 mph. There was widespread damage along the tornado track in Olive Branch. Numerous trees and power lines were knocked down. Four homes were destroyed while numerous other homes suffered some degree of damage. Streets that suffered the heaviest damage included Roberta Street, College Street, Blocker Street, Chickasaw Drive, Cherokee Drive, Sequoia Lane, Seminole Drive and Magnolia Drive. Several schools and public buildings were also damaged including the Olive Branch Elementary, Middle and High Schools, the Chickasaw Elementary School, the Olive Branch Community Center and the Olive Branch City Shop. The Olive Branch Middle School alone suffered $500,000 in damage. The tornado cleanup costs totaled $350,000 for the city of Olive Branch. There was one minor injury associated with the tornado in Olive Branch.

Southaven

None Reported -- -- -- -- --

Walls

None Reported -- -- -- -- --

Unincorporated Area

DE SOTO CO. 4/28/1962 F2 0/1 $1,988,709 --

DE SOTO CO. 2/11/1965 F2 0/1 $190,663 --

DE SOTO CO. 6/30/1967 F1 0/0 $0 --

DE SOTO CO. 4/3/1968 F2 0/4 $0 --

DE SOTO CO. 5/16/1968 F2 0/7 $1,725,833 --

DE SOTO CO. 6/24/1969 F1 0/0 $0 --

DE SOTO CO. 4/24/1970 F3 0/5 $15,479 --



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Property Damage*

Details

DE SOTO CO. 11/27/1973 F1 0/10 $1,352,680

Three tornadoes moved northeastward from about 4 miles northwest of Eudora into Horn Lake and Southaven areas. Newspaper said "damage was very severe in a 2-mile-wide belt through county." The 3 damage paths were separated by mile-wide sections with little or no damage. 212 homes destroyed. 2 were fixed dwellings, 210 were mobile homes. 75 persons were injured and there was 1 fatality. At least 13 persons were hospitalized. Damage estimated $1,000,000.00 to $1,500,000.00. At least 3 schools damaged. (a) The first tornado damage path started on Wilson Mill Road, about 1 mile east of Texas Gas pumping station, extended northeastward 4-1/2 miles a little past intersection of Highway 301 and Austin Road. (b) A second damage path began near the intersection of Star Landing Road and Highway 301 and extended about 8 miles northeastward through eastern Horn Lake to the Southaven Elementary School in Central Southaven. (c) The third damage path was shorter and less defined, about 2-3/4 miles long but included the DeSoto Woods and Redwood Estates mobile homes where most injuries occurred.

DE SOTO CO. 11/27/1973 F1 0/15 $1,352,680




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Property Damage*

Details

DE SOTO CO. 11/27/1973 F2 1/50 $1,352,680


DE SOTO CO. 3/12/1986 F1 0/0 $547,984 --

DE SOTO CO. 1/19/1988 F2 0/1 $5,076,839

A tornado moved northeast at 55 mph and touched down 4 separate times in a 9.5 mile stretch. Near the middle portion of the track, the tornado set down for 3 miles and inflicted its worst damage in subdivision south of Southaven. In total, 4 homes were destroyed, 10 had major damage and 79 minor damage. Damage was estimated at on half million dollars. The tornado also derailed 14 cars of a train. Other outbuildings and fences also received heavy damage. Total damage from the tornado was estimated at 1.2 million dollars.

Nesbit 8/5/1993 F0 0/0 $8,313 Numerous trees were knocked down.

LEWISBURG 11/24/2001 F2 0/9 $2,577,348

The tornado began just southwest of Lewisburg in eastern De Soto county and moved northeast. Nineteen homes were destroyed and 119 homes were damaged. Numerous trees were also knocked down.

NORFOLK 2/5/2008 EF0 0/0 $55,790

A tornado touched down near Old Highway 61 and damaged a farm building roof. The tornado tracked northeast for a little more than 2 miles, lifting along Norfolk Road. A pivot irrigation system was damaged and power poles were knocked down along Norfolk Road.



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Property Damage*

Details

HORN LAKE DESOTO ARP 2/5/2008 EF2 0/0 $31,688,840

A tornado touched down at Southaven High School and tracked northeast crossing into Shelby County, Tennessee, northeast of the intersection of Stateline Road and Airways Boulevard. Roughly 30 windows were blown out of the High School. The school also sustained minor roof damage. Damage at the high school was classified EF-0. Many homes in the Carriage Hills subdivision sustained minor damages as well. Further northeast, more significant damage occurred near the intersection of Stateline Road and Airways Boulevard in the warehouse area. Three warehouses were destroyed including the Cooper Lighting Plant. A gas station was damaged as well. Damage was classified as EF-2 in this area. Numerous trees, power poles, and lines were knocked down. Minor roof damage occurred along the path as well.

MILLER 7/30/2009 EF2 0/0 $6,718,729

A tornado touched down on Highway 305, four tenths of a mile south of College Road, southeast of Olive Branch. The tornado moved northeast on a non-continuous track. Several subdivisions had numerous trees and power lines knocked down. Some of which fell onto houses damaging them. The hardest hit area was in the Bethel Park Subdivision. Seven homes were destroyed, 15 homes sustained major damage while at least 113 other homes received minor damage including damage such as minor roof or shingle damage. In addition, one business sustained major damage and another business sustained minor damage. The tornado lifted just east of the intersection of Center Hill Road and Knightsbridge Road.

NESBIT 5/2/2010 EF0 0/0 $11,017

A weak tornado touched down just north of Interstate 69 near Tulane Road and traveled northeast for about 1 mile before lifting near the Nesbit Road. Several very large trees were knocked down and a couple of them were snapped off. Some shingle damage was noted as well.


There have been several significant tornado events in DeSoto County. The text below describes one of the major events and associated impacts on the county. From April 25 to 28, 2011, the largest tornado outbreak ever recorded affected the Southern, Midwestern, and Northeastern U.S., leaving catastrophic destruction in its wake, especially across the states of Alabama and Mississippi. Although no tornadoes were reported in DeSoto County, it is notable that



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surrounding areas experienced much higher magnitude tornadoes and that these are possible in the county.

PROBABILITY OF FUTURE OCCURRENCES According to historical information, tornado events pose a significant threat to DeSoto County. The probability of future tornado occurrences affecting DeSoto County is highly likely (100 percent annual probability).

B.2.15 Winter Storm and Freeze

LOCATION AND SPATIAL EXTENT Nearly the entire continental United States is susceptible to winter storm and freeze events. Some ice and winter storms may be large enough to affect several states, while others might affect limited, localized areas. The degree of exposure typically depends on the normal expected severity of local winter weather. DeSoto County is not accustomed to severe winter weather conditions and seldom receives severe winter weather, even during the winter months. Events tend to be mild in nature; however, this creates a situation where even relatively small accumulations of snow, ice, or other wintery precipitation can lead to losses and damage due to the fact that these events are not commonplace. Given the atmospheric nature of the hazard, the entire county has uniform exposure to a winter storm.

HISTORICAL OCCURRENCES Winter weather has resulted in one disaster declaration in DeSoto County in 1994.22 According to the National Climatic Data Center, there have been a total of 34 recorded winter storm events in DeSoto County since 1996 (Table B.26).23 These events resulted in almost $50,000 (2016 dollars) in damages.24 Detailed information on the recorded winter storm events can be found in Table B.27.

TABLE B.26: SUMMARY OF WINTER STORM EVENTS IN DESOTO COUNTY

Location Number of




DeSoto County 34 0/0 $49,703 $2,485


TABLE B.27: HISTORICAL WINTER STORM IMPACTS IN DESOTO COUNTY Location Date Type Deaths/Injuries Property Damage*

Hernando


Horn Lake


22 A complete listing of historical disaster declarations can be found in Section 4: Hazard Identification. 23 These ice and winter storm events are only inclusive of those reported by the National Climatic Data Center (NCDC) from

1996 through April 2015. It is likely that additional winter storm conditions have affected DeSoto County. 24 Adjusted dollar values were calculated based on the average Consumer Price Index for a given calendar year. This index value

has been calculated every year since 1913. For 2015, the June 2015 monthly index was used.



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Location Date Type Deaths/Injuries Property Damage*

Olive Branch


Southaven


Walls


Unincorporated Area

DE SOTO (ZONE) 2/1/1996 Winter Storm 0/0 $30,623

DE SOTO (ZONE) 1/15/1998 Winter Storm 0/0 $0

DE SOTO (ZONE) 12/22/1998 Ice Storm 0/0 $1,474

DE SOTO (ZONE) 1/27/2000 Heavy Snow 0/0 $0

DE SOTO (ZONE) 12/13/2000 Ice Storm 0/0 $13,951





DE SOTO (ZONE) 2/1/2007 Winter Weather 0/0 $0

DE SOTO (ZONE) 4/6/2007 Frost/freeze 0/0 $0

DE SOTO (ZONE) 4/7/2007 Frost/freeze 0/0 $0


























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There have been several severe winter weather events in DeSoto County. The text below describes three of the major events and associated impacts on the county. Similar impacts can be expected with severe winter weather. February 1994 A damaging ice storm with freezing rain accumulations of 3 to 6 inches occurred across north Mississippi from February 9-11. Most estimates calculate this storm as the worst on record since 1951 with damages occurring across parts of Arkansas, Tennessee, Alabama, Louisiana, and Texas, as well as 26 counties in Mississippi, which sustained damages of roughly $300 million. According to power companies, more than 200,000 homes were left without power at the height of the storm, and water provides estimate nearly 175,000 homes were without water during this time period. Agriculture also took an especially hard hit as nearly 5 percent of the state’s pecan trees were destroyed. 25 December 1998 Much of north Mississippi was hit with an ice storm. Most counties reported between 0.25 to 0.5 inches of ice on their roads with some locations in the southern part of the region reporting as much as 3 inches of ice. The ice caused numerous power outages and brought down many trees and power lines. Thousands of people in north Mississippi were without power, some for as long as one week. Christmas travel was severely hampered for several days with motorists stranded at airports, bus stations, and truck stops. Travel did not return to normal until after Christmas in some locations. January 2000 A winter storm brought a swath of heavy snow across north central Mississippi. The snow began falling over western portions of the area during the early morning of the 27th and spread eastward during the day. The snow was heavy at times and did not end until the morning of the 28th. Snowfall amounts generally ranged from 4 to 10 inches. The heaviest amounts fell along the Highway 82 corridor from Greenville to Starkville where isolated snow depths of 12 inches were reported. Damage from the heavy snow was relatively minimal with reports limited to a few collapsed roofs and downed trees. Power outages were sporadic, but travelling was more than just an inconvenience as numerous reports of vehicles running off the road were received. Winter storms throughout the planning area have several negative externalities including hypothermia, cost of snow and debris cleanup, business and government service interruption, traffic accidents, and power outages. Furthermore, citizens may resort to using inappropriate heating devices that could to fire or an accumulation of toxic fumes.

PROBABILITY OF FUTURE OCCURRENCES Winter storm events will continue to occur in DeSoto County. Based on historical information, the probability is likely (between 10 and 100 percent annual probability).

B.2.16 Conclusions on Hazard Risk The hazard profiles presented in this subsection were developed using best available data and result in what may be considered principally a qualitative assessment as recommended by FEMA in its “How-to” guidance document titled Understanding Your Risks: Identifying Hazards and Estimating Losses (FEMA

25 Pfost, Russell L. Disastrous Mississippi Ice Storm of 1994. National Weather Service Forecast Office. Jackson, Mississippi.



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Publication 386-2). It relies heavily on historical and anecdotal data, stakeholder input, and professional and experienced judgment regarding observed and/or anticipated hazard impacts. It also carefully considers the findings in other relevant plans, studies, and technical reports.

HAZARD EXTENT Table B.28 describes the extent of each natural hazard identified for DeSoto County. The extent of a hazard is defined as its severity or magnitude, as it relates to the planning area.

TABLE B.28: EXTENT OF DESOTO COUNTY HAZARDS Flood-related Hazards

Dam and Levee Failure Dam Failure extent is defined using the Mississippi Department of Environmental Quality criteria (Table 5.3). Twenty-six dams are classified as high-hazard in DeSoto County.

Erosion

The extent of erosion can be defined by the measurable rate of erosion that occurs. There are no erosion rate records located in DeSoto County. Some areas of minimal erosion have been identified by local coordinators, but no major areas of severe erosion were noted.

Flood

Flood extent can be measured by the amount of land and property in the floodplain as well as flood height and velocity. The amount of land in the floodplain accounts for 24.5 percent of the total land area in DeSoto County. Flood depth and velocity are recorded via United States Geological Survey stream gages throughout the region. While a gage does not exist for each participating jurisdiction, there is one at or near many areas. The greatest peak discharge recorded for the county was at the Coldwater River near Arkabutla Dam on January 22, 1938. Water reached a discharge of 30,200 cubic feet per second. The highest stream gage height was also on the Coldwater River near Arkabutla Dam with a height that was recorded at 42.56 feet on February 16, 1950.

Fire-related Hazards

Drought

Drought extent is defined by the U.S. Drought Monitor Classifications which include Abnormally Dry, Moderate Drought, Severe Drought, Extreme Drought, and Exceptional Drought. According to the U.S. Drought Monitor Classifications, the most severe drought condition is Exceptional. DeSoto County has received this ranking once over the 17-year reporting period.

Lightning

According to the Vaisala’s flash density map (Figure 5.8), DeSoto County is located in an area that experiences 4 to 12 lightning flashes per square kilometer per year. It should be noted that future lightning occurrences may exceed these figures.

Wildfire

Wildfire data was provided by the Mississippi Forestry Commission and is reported annually by county from 2012-2016. The greatest number of fires to occur in DeSoto County in any year was 3 in 2014. The greatest number of acres to burn in the county in a single year occurred in 2014 when 68 acres were burned. Although this data lists the extent that has occurred, larger and more frequent wildfires are possible throughout the county.



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Geologic Hazards

Earthquake

Earthquake extent can be measured by the Richter Scale (Table 5.15), the Modified Mercalli Intensity (MMI) scale (Table 5.16), and the distance of the epicenter from DeSoto County. According to data provided by the National Geophysical Data Center, the greatest earthquake to impact the county had a MMI of IV (moderate) and a Richter Scale magnitude of 5.3 (reported on November 9, 1968). The epicenter of this earthquake was located 377.0 km away.

Landslide

As noted above in the landslide profile, there is no extensive history of landslides in DeSoto County and landslide events typically occur in isolated areas. This provides a challenge when trying to determine an accurate extent for the landslide hazard. However, when using USGS landslide susceptibility index, extent can be measured with incidence, which is low across half of the county. The remainder of the county has moderate incidence. There is also low susceptibility throughout some of the county but there are areas of high susceptibility in the northwestern corner and center of the county.

Land Subsidence/ Sinkhole

The extent of land subsidence can be defined by the measurable rate of subsidence that occurs. There are no subsidence rate records located in DeSoto County nor is there any significant historical record of events. The largest potential event might be as a large as 10,000 cubic yards.

Wind-related Hazards

Extreme Heat

The extent of extreme heat can be measured by the record high temperature recorded. Official long term temperature records are not kept for any areas in DeSoto County. However, the highest recorded temperature in Tunica (southwest of the county) was 106°F in 2000.

Hailstorm Hail extent can be defined by the size of the hail stone. The largest hail stone reported in DeSoto County was 2.0 inches (last reported on November 15, 2005). It should be noted that future events may exceed this.

Hurricane and Tropical Storm

Hurricane extent is defined by the Saffir-Simpson Scale which classifies hurricanes into Category 1 through Category 5 (Table 5.23). The greatest classification of hurricane to traverse directly through DeSoto County was an Unnamed 1888 Storm which carried tropical force winds of 60 knots upon arrival in the county.

Severe Thunderstorm/ High Wind

Thunderstorm extent is defined by the number of thunder events and wind speeds reported. According to a 61-year history from the National Climatic Data Center, the strongest recorded wind event in DeSoto County was reported on June 13, 2011 at 83 knots (approximately 96 mph). It should be noted that future events may exceed these historical occurrences.

Tornado

Tornado hazard extent is measured by tornado occurrences in the US provided by FEMA (Figure 5.21) as well as the Fujita/Enhanced Fujita Scale (Tables 5.28 and 5.29). The greatest magnitude reported in DeSoto County was an F3 (reported on April 24, 1970).

Winter Storm and Freeze

The extent of winter storms can be measured by the amount of snowfall received (in inches). The greatest snowfall reported in Olive was 14.3 inches in 1963.

PRIORITY RISK INDEX RESULTS In order to draw some meaningful planning conclusions on hazard risk for DeSoto County, the results of the hazard profiling process were used to generate countywide hazard classifications according to a



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“Priority Risk Index” (PRI). More information on the PRI and how it was calculated can be found in Section 5.18.2. Table B.29 summarizes the degree of risk assigned to each category for all initially identified hazards based on the application of the PRI. Assigned risk levels were based on the detailed hazard profiles developed for this subsection, as well as input from the Regional Hazard Mitigation Council. The results were then used in calculating PRI values and making final determinations for the risk assessment.

TABLE B.29: SUMMARY OF PRI RESULTS FOR DESOTO COUNTY

Hazard

Category/Degree of Risk

Probability Impact Spatial Extent Warning Time Duration PRI

Score

Flood-related Hazards

Dam Failure and Levee Failure Unlikely Critical Large Less than 6 hours Less than 6 hours 2.5

Erosion Likely Minor Small More than 24 hours More than 1 week 2.1

Flood Highly Likely Critical Moderate 6 to 12 hours Less than 24 hours 3.2


Drought Likely Limited Large More than 24 hours More than 1 week 2.8

Lightning Highly Likely Limited Small 6 to 12 hours Less than 6 hours 2.6

Wildfire Highly Likely Minor Small Less than 6 hours Less than 1 week 2.6

Geologic Hazards

Earthquake Likely Critical Large Less than 6 hours Less than 6 hours 3.1

Landslide Possible Minor Small Less than 6 hours Less than 24 hours 1.9

Land Subsidence/Sinkhole Possible Minor Small Less than 6 hours Less than 24 hours 1.9


Extreme Heat Likely Minor Large More than 24 hours More than 1 week 2.5

Hailstorm Highly Likely Limited Moderate 6 to 12 hours Less than 6 hours 2.8

Hurricane and Tropical Storm Possible Limited Large More than 24 hours Less than 24 hours 2.3

Severe Thunderstorm/High Wind Highly Likely Critical Moderate 6 to 12 hours Less than 6 hours 3.1

Tornado Highly Likely Catastrophic Small Less than 6 hours Less than 6 hours 3.3

Winter Storm and Freeze Likely Limited Moderate More than 24 hours Less than 1 week 2.5

B.2.17 Final Determinations on Hazard Risk The conclusions drawn from the hazard profiling process for DeSoto County, including the PRI results and input from the Regional Hazard Mitigation Council, resulted in the classification of risk for each identified hazard according to three categories: High Risk, Moderate Risk, and Low Risk (Table B.30). For purposes of these classifications, risk is expressed in relative terms according to the estimated impact that a hazard will have on human life and property throughout all of DeSoto County. A more quantitative analysis to estimate potential dollar losses for each hazard has been performed separately, and is described in Section 6: Vulnerability Assessment and below in Section B.3. It should be noted that although some hazards are classified below as posing low risk, their occurrence of varying or unprecedented magnitudes



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is still possible in some cases and their assigned classification will continue to be evaluated during future plan updates.

TABLE B.30: CONCLUSIONS ON HAZARD RISK FOR DESOTO COUNTY

B.3 DESOTO COUNTY VULNERABILITY ASSESSMENT This subsection identifies and quantifies the vulnerability of DeSoto County to the significant hazards previously identified. This includes identifying and characterizing an inventory of assets in the county and assessing the potential impact and expected amount of damages caused to these assets by each identified hazard event. More information on the methodology and data sources used to conduct this assessment can be found in Section 6: Vulnerability Assessment.

B.3.1 Asset Inventory Table B.31 lists the estimated number of improved properties and the total value of improvements for DeSoto County and its participating jurisdictions (study area of vulnerability assessment). Because digital parcel data was not available for most communities, data obtained from Hazus-MH 3.1 inventory was utilized to complete the analysis.

TABLE B.31: IMPROVED PROPERTY IN DESOTO COUNTY

Location Counts of Improved

Property Total Value of Improvements

Hernando 6,576 $1,876,565,000

HIGH RISK

Tornado

Flood

Severe Thunderstorm/High Wind

Earthquake

MODERATE RISK

Hailstorm

Drought

Lightning

Wildfire

Dam and Levee Failure

Extreme Heat

Winter Storm and Freeze

LOW RISK

Hurricane and Tropical Storm

Erosion

Landslide

Land Subsidence/Sinkhole



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Location Counts of Improved

Property Total Value of Improvements

Horn Lake 8,470 $2,097,067,000

Olive Branch 12,779 $3,953,300,000

Southaven 19,594 $5,566,173,000

Walls 892 $227,950,000

Unincorporated Area 10,567 $2,663,858,000

DESOTO COUNTY TOTAL 58,878 $16,384,913,000 Source: Hazus-MH 3.1

Table B.32 lists the fire stations, police stations, medical care facilities, emergency operations centers (EOCs), schools, shelters, government buildings, water/utility infrastructure, and other facilities located in DeSoto County according to Hazus-MH Version 3.1 data that was reviewed and updated by local officials. In addition, Figure B.13 shows the locations of critical facilities in DeSoto County. Table B.42, at the end of this subsection, shows a complete list of the critical facilities by name, as well as the hazards that affect each facility. As noted previously, this list is not all-inclusive and only includes information provided through Hazus which was updated, as best as possible, with local knowledge.

TABLE B.32: CRITICAL FACILITY INVENTORY IN DESOTO COUNTY

Location Fire

Stations Police

Stations Medical

Care EOC Schools Gov’t*

Water/ Utility*

Shelter* Other*

Hernando 5 2 0 1 6 0 0 0 0

Horn Lake 4 2 0 0 5 0 0 0 0

Olive Branch 5 1 2 0 15 0 0 0 0

Southaven 5 2 1 0 11 0 0 0 0

Walls 0 0 0 0 1 0 0 0 0

Unincorporated Area 2 0 0 0 3 0 0 0 0

DESOTO COUNTY TOTAL

21 7 3 1 41 0 0 0 0

*All counties were not able to attain information on these facility types, however, this should not imply that these counties do not have any of these types of facilities. Instead, it should be noted that as this information is collected, it will be incorporated in future updates of the plan. Source: Hazus-MH 3.1, Local Officials



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FIGURE B.13: CRITICAL FACILITY LOCATIONS IN DESOTO COUNTY

Source: Hazus-MH 3.1, Local Officials

B.3.2 Social Vulnerability In addition to identifying those assets potentially at risk to identified hazards, it is important to identify and assess those particular segments of the resident population in DeSoto County that are potentially at risk to these hazards. Table B.33 lists the population by jurisdiction according to U.S. Census 2010 population estimates. The total population in DeSoto County according to Census data was 161,252 persons. Additional population estimates are presented above in Section B.1.

TABLE B.33: TOTAL POPULATION IN DESOTO COUNTY Location Total 2010 Population

Hernando 14,090

Horn Lake 26,066

Olive Branch 33,484

Southaven 48,982

Walls 1,162



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Location Total 2010 Population

Unincorporated Area 37,468

DESOTO COUNTY TOTAL 161,252

Source: United States Census Bureau, 2010 Census

In addition, Figure B.14 illustrates the population density per square kilometer by census tract as it was reported by the U.S. Census Bureau in 2010. As can be seen in the figure, the population is spread out with concentrations in large municipal areas such as Horn Lake and Olive Branch.

FIGURE B.14: POPULATION DENSITY IN DESOTO COUNTY

Source: United States Census Bureau, 2010 Census

B.3.3 Development Trends and Changes in Vulnerability Since the previous county hazard mitigation plan was approved, DeSoto County has experienced limited growth and development. Table B.34 shows the number of building units constructed since 2010 according to the U.S. Census American Community Survey.



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TABLE B.34: BUILDING COUNTS FOR DESOTO COUNTY

Jurisdiction Total Housing Units (2014)

Units Built 2010 or later

% Building Stock Built Post-2010

Hernando 5,278 208 3.94%

Horn Lake 9,971 12 0.12%

Olive Branch 13,432 375 2.79%

Southaven 19,414 144 0.74%

Walls 415 12 2.89%

Unincorporated Area 14,193 330 2.33%

DESOTO COUNTY TOTAL 62,703 1,081 1.72%

Source: United States Census Bureau, 2010-2014 American Community Survey 5-Year Estimates

Table B.35 shows population growth estimates for the county from 2010 to 2014 based on the U.S. Census American Community Survey.

TABLE B.35: POPULATION GROWTH FOR DESOTO COUNTY

Jurisdiction Population Estimates % Change

2010-2014 2010 2011 2012 2013 2014

Hernando 13,253 13,679 14,117 14,437 14,723 11.09%

Horn Lake 25,495 25,901 26,120 26,350 26,486 3.89%

Olive Branch 31,910 32,796 33,484 34,050 34,543 8.25%

Southaven 46,743 48,005 48,981 49,728 50,389 7.80%

Walls 584 700 725 914 1,099 88.18%

Unincorporated Area 36,730 37,405 38,109 38,496 39,026 6.25%

DESOTO COUNTY TOTAL 154,715 158,486 161,536 163,975 166,266 7.47%

Source: United States Census Bureau, 2006-2010, 2007-2011, 2008-2012, 2009-2013, and 2010-2014 American Community Survey 5-Year Estimates

Based on the data above, there has been a low rate of residential development and population growth in the county since 2010. However, it is notable that the City of Hernando has experienced a slightly higher rate of development compared to the rest of the county, resulting in an increased number of structures that are vulnerable to the potential impacts of the identified hazards. Additionally, there was a substantial rate of population growth in the Town of Walls. As a result, there are now greater numbers of people exposed to the identified hazards in some areas. Therefore, development and population growth have impacted the county’s vulnerability since the previous local hazard mitigation plan was approved and there has been a slight increase in the overall vulnerability as well as a significant increase in certain areas and communities. It is also important to note that as development increases in the future, greater populations and more structures and infrastructure will be exposed to potential hazards if development occurs in the floodplains, landside susceptibility areas, or high wildfire risk areas.



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B.3.4 Vulnerability Assessment Results

As noted in Section 6: Vulnerability Assessment, only hazards with a specific geographic boundary, available modeling tool, or sufficient historical data allow for further analysis. Those results, specific to DeSoto County, are presented here. All other hazards are assumed to impact the entire planning region (drought, extreme heat, hailstorm, lightning, severe thunderstorm/high wind, tornado, and winter storm) or, due to lack of data, analysis would not lead to credible results (dam and levee failure, erosion, and land subsidence/sinkhole). The total county exposure, and thus risk to these hazards, was presented in Table B.31. The hazards to be further analyzed in this subsection include: flood, landslide, wildfire, earthquake, and hurricane and tropical storm winds. The annualized loss estimate for all hazards is presented near the end of this subsection in Table B.41.

FLOOD Historical evidence indicates that DeSoto County is susceptible to flood events. A total of 60 flood events have been reported by the National Climatic Data Center resulting in $11.8 million (2016 dollars) in property damage and two fatalities. On an annualized level, these damages amounted to $814,334 for DeSoto County. In order to assess flood risk, a GIS-based analysis was used to estimate exposure to flood events using Digital Flood Insurance Rate Map (DFIRM) data in combination with improved property records for the county. The determination of value at-risk (exposure) was calculated using GIS analysis by summing the values for improved properties that were located within an identified floodplain. Due to a lack of digital parcel data in most counties, it was determined that an analysis using the inventory from Hazus-MH 3.1 would be used, though it should be noted that the data will merely be an estimation and may not reflect actual counts or values located in the floodplain. Indeed, in almost all cases, this analysis likely overestimates the amount of property at risk. Table B.36 presents the potential at-risk property. Both the number of parcels and the approximate value are presented.

TABLE B.36: ESTIMATED EXPOSURE OF PROPERTY TO THE FLOOD HAZARD26

Location 1.0-percent ACF

Approx. Number of Improvements

Approx. Improved Value

Hernando 2,015 $560,554,000

Horn Lake 2,233 $588,993,000

Olive Branch 2,979 $1,057,233,000

Southaven 7,031 $2,064,184,000

Walls 832 $207,184,000


DESOTO COUNTY TOTAL

20,172 $5,759,613,000

Source: Federal Emergency Management Agency DFIRM and Hazus MH 3.1

26 As noted in Section 6.4, no building-specific data, such as building footprints, was available to determine buildings at risk. As

a result of this data limitation, at-risk census block building counts and values of the structures were used.



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Social Vulnerability Figure B.15 is presented to gain a better understanding of at-risk population by evaluating census tract level population data against mapped floodplains. There are areas of concern in several of the population centers. Indeed, nearly every incorporated municipality is potentially at risk of being impacted by flooding in some areas of its jurisdiction. Therefore, further investigation in these areas may be warranted.

FIGURE B.15 : POPULATION DENSITY NEAR FLOODPLAINS IN DESOTO COUNTY

Source: Federal Emergency Management Agency DFIRM, United States Census 2010

Critical Facilities The critical facility analysis revealed that there are five critical facilities located in the floodplain. (Please note, as previously indicated, this analysis does not consider building elevation, which may negate risk.) All of these facilities are located in the 1.0 percent annual chance flood zone, and they include 2 fire stations and 3 schools. A list of specific critical facilities and their associated risk can be found in Table B.42 at the end of this subsection. In conclusion, a flood has the potential to impact many existing and future buildings, facilities, and populations in DeSoto County, though some areas are at a higher risk than others. All types of structures in a floodplain are at-risk, though elevated structures will have a reduced risk. Such site-specific vulnerability determinations are outside the scope of this assessment but may be considered during



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future plan updates. Furthermore, areas subject to repetitive flooding should be analyzed for potential mitigation actions.

LANDSLIDE Steeper topography in some areas of DeSoto County makes the planning area susceptible to landslides. Although no major landslide incidents have been reported in the county, it should be noted that United States Geological Survey information on historic events is not well-documented so the data may be incomplete. There may be additional historical landslide occurrences that were not reported. In order to complete the vulnerability assessment for landslides in DeSoto County, GIS analysis was used. The potential dollar value of exposed property can be determined using the USGS Landslide Susceptibility Index (detailed in Section 5: Hazard Profiles), census block data from Hazus or county-level tax parcel data, and GIS analysis. Table B.37 presents the potential at-risk property where available. Only a portion of the region is identified as being in a moderate incidence/high susceptibility or low incidence/high susceptibility area by the USGS landslide data. These incidence levels were used to identify areas of concern for the analysis below.

TABLE B.37: TOTAL POTENTIAL AT-RISK PARCELS FOR THE LANDSLIDE HAZARD

Location

Low Incidence/ High Susceptibility Area

Moderate Incidence/ High Susceptibility Area

Approx. Number of

Improvements


Approx. Number of

Improvements


Hernando 0 $0 6,576 $1,876,565,000

Horn Lake 0 $0 8,094 $1,990,575,000

Olive Branch 0 $0 2,219 $614,236,000

Southaven 0 $0 19,498 $5,540,560,000

Walls 119 $36,656,000 175 $47,740,000

Unincorporated Area 645 $127,223,000 3,649 $924,249,000

DESOTO COUNTY TOTAL

764 $163,879,000 40,211 $10,993,925,000

Source: United States Geological Survey and Hazus-MH 3.1

Social Vulnerability Given low incidence across the most of the county, it is assumed that the total population is at relatively low risk. However, some populations in the western and central part of the county are considered at slightly higher risk due to their location in areas of high susceptibility. Critical Facilities There are no critical facilities located in a low incidence/high susceptibility area. Several critical facilities are located in the moderate incidence/high susceptibility area. There are 50 critical facilities located in this zone. This includes 1 EOC, 14 fire stations, 1 medical care facility, 6 police stations, and 28 schools. A list of specific critical facilities and their associated risk can be found in Table B.42 at the end of this subsection.



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In conclusion, a landslide has the potential to impact all existing and future buildings, critical facilities, and populations in DeSoto County. Specific vulnerabilities for DeSoto County assets will be greatly dependent on their individual design and the mitigation measures in place where appropriate. Such site-specific vulnerability determinations are outside the scope of this assessment but will be considered during future plan updates if data becomes available.

WILDFIRE Although historical evidence indicates that DeSoto County is susceptible to wildfire events, there are few reports which include information on historic dollar losses. Therefore, it is difficult to calculate a reliable annualized loss figure. Annualized loss is considered negligible though it should be noted that a single event could result in significant damages throughout the county. To estimate exposure to wildfire, building data was obtained from Hazus-MH 3.1 for most counties which includes information that has been aggregated at the census block level and which has been deemed useful for analyzing wildfire vulnerability. However, it should be noted that the accuracy of Hazus data is somewhat lower than that of parcel data. For the critical facility analysis, areas of concern were intersected with critical facility locations. Figure B.16 shows the Wildland Urban Interface Risk Index (WUIRI) data, which is a data layer that shows a rating of the potential impact of a wildfire on people and their homes. The key input, Wildland Urban Interface (WUI), reflects housing density (houses per acre) consistent with Federal Register National standards. The location of people living in the WUI and rural areas is key information for defining potential wildfire impacts to people and homes. Initially provided as raster data, it was converted to a polygon to allow for analysis. The Wildland Urban Interface Risk Index data ranges from 0 to -9 with lower values being most severe (as noted previously, this is only a measure of relative risk). Figure B.17 shows the areas of analysis where any grid cell is less than -5. Areas with a value below -5 were chosen to be displayed as areas of risk because this showed the upper echelon of the scale and the areas at highest risk. Table B.38 shows the results of the analysis.



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FIGURE B.16: WUI RISK INDEX AREAS IN DESOTO COUNTY

Source: Southern Wildfire Risk Assessment Data



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FIGURE B.17: WILDFIRE RISK AREAS IN DESOTO COUNTY

Source: Southern Wildfire Risk Assessment Data

TABLE B.38: EXPOSURE OF IMPROVED PROPERTY27 TO WILDFIRE RISK AREAS

Location Wildfire Risk

Approx. Number of Improvements


Hernando 3,300 $918,327,000

Horn Lake 2,158 $513,199,000

Olive Branch 4,356 $1,452,851,000

Southaven 7,380 $2,063,413,000

Walls 367 $97,620,000


DESOTO COUNTY TOTAL

24,571 $6,754,028,000

Source: Southern Wildfire Risk Assessment and Hazus-MH 3.1

27 Parcel/Building Footprint data was not available for DeSoto County. Therefore, building counts and values were pulled from

Hazus-MH at the census block level and approximate improved value was calculated.



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Social Vulnerability Given some level of susceptibility across the entire county, it is assumed that the total population is at risk to the wildfire hazard. Determining the exact number of people in certain wildfire zones is difficult with existing data and could be misleading. Critical Facilities The critical facility analysis revealed that there are no critical facilities located in wildfire areas of concern. It should be noted, that several factors could impact the spread of a wildfire putting all facilities at risk. A list of specific critical facilities and their associated risk can be found in Table B.42 at the end of this subsection. In conclusion, a wildfire event has the potential to impact many existing and future buildings, critical facilities, and populations in DeSoto County.

EARTHQUAKE As the Hazus-MH model suggests below, and historical occurrences confirm, any significant earthquake activity in the area is likely to inflict moderate damage to the county. Hazus-MH 3.1 estimates a total annualized loss of $5,939,000 which includes buildings, contents, and inventory throughout the county. For the earthquake hazard vulnerability assessment, a probabilistic scenario was created to estimate the average annualized loss28 for the county. The results of the analysis are generated at the census tract level within Hazus-MH and then aggregated to the county level. Since the scenario is annualized, no building counts are provided. Losses reported included losses due to structure failure, building loss, contents damage, and inventory loss. They do not include losses to business interruption, lost income, or relocation. Table B.39 summarizes the findings with results rounded to the nearest thousand.

TABLE B.39: AVERAGE ANNUALIZED LOSS ESTIMATIONS FOR EARTHQUAKE HAZARD

Location Structural Damage

Non-Structural Damage

Contents Damage

Inventory Loss

Total Annualized Loss

DeSoto County $941,000 $3,541,000 $1,397,000 $60,000 $5,939,000

Source: Hazus-MH 3.1

Social Vulnerability It can be assumed that all existing and future populations are at risk to the earthquake hazard.

Critical Facilities The Hazus-MH probabilistic analysis did not indicate that any critical facilities would sustain measurable damage in an earthquake event. However, all critical facilities should be considered at-risk to minor to moderate damage should an event occur. A list of specific critical facilities and their associated risk can be found in Table B.42 at the end of this subsection. In conclusion, an earthquake has the potential to impact all existing and future buildings, facilities, and populations in DeSoto County. Specific vulnerabilities for these assets will be greatly dependent on their individual design and the mitigation measures in place. Such site-specific vulnerability determinations are

28 Annualized loss is defined by Hazus-MH as the expected value of loss in any one year.



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outside the scope of this assessment but may be considered during future plan updates. The Hazus-MH scenario indicates that minimal to moderate damage is expected from an earthquake occurrence. While DeSoto County may not experience a catastrophic earthquake (the greatest on record is a magnitude V MMI), localized damage is possible with a moderate to larger scale occurrence.

HURRICANE AND TROPICAL STORM Historical evidence indicates that DeSoto County has some risk to the hurricane and tropical storm hazard. There has been one disaster declaration due to hurricanes (Hurricane Katrina). Several tracks have come near or traversed through the county, as shown and discussed in Section B.2.12. Hazus-MH 3.1 estimates a total annualized loss of $157,000 which includes buildings, contents, and inventory throughout the county. Hurricanes and tropical storms can cause damage through numerous additional hazards such as flooding, erosion, tornadoes, and high winds, thus it is difficult to estimate total potential losses from these cumulative effects. The current Hazus-MH hurricane model only analyzes hurricane winds and is not capable of modeling and estimating cumulative losses from all hazards associated with hurricanes; therefore, only hurricane winds are analyzed in this subsection. Hazus-MH 3.1 was used to determine average annualized losses29 for the county as shown below in Table B.40. Only losses to buildings, inventory, and contents are included in the results.

TABLE B.40: ANNUALIZED LOSS ESTIMATIONS FOR HURRICANE WIND HAZARD

Location Building Damage Contents Damage

Inventory Loss

Total Annualized Loss

DeSoto County $140,000 $17,000 $0 $157,000

Source: Hazus-MH 3.1

Social Vulnerability Given some equal susceptibility across the entire county, it is assumed that the total population, both current and future, is at risk to the hurricane and tropical storm hazard. Critical Facilities Given equal vulnerability across DeSoto County, all critical facilities are considered to be at risk. Some buildings may perform better than others in the face of such an event due to construction and age, among factors. Determining individual building response is beyond the scope of this plan. However, this plan will consider mitigation action for especially vulnerable structures and/or critical facilities to mitigate against the effects of the hurricane hazard. A list of specific critical facilities can be found in Table B.42 at the end of this subsection. In conclusion, a hurricane event has the potential to impact many existing and future buildings, critical facilities, and populations in DeSoto County.

29 Annualized loss is defined by Hazus-MH as the expected value of loss in any one year.



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CONCLUSIONS ON HAZARD VULNERABILITY Table B.41 presents a summary of annualized loss for each hazard in DeSoto County. Due to the reporting of hazard damages primarily at the county level, it was difficult to determine an accurate annualized loss estimate for each municipality. Therefore, an annualized loss was determined through the damage reported through historical occurrences at the county level. These values should be used as an additional planning tool or measure risk for determining hazard mitigation strategies throughout the county.

TABLE B.41: ANNUALIZED LOSS FOR DESOTO COUNTY

Event DeSoto County

Flood-related Hazards

Dam and Levee Failure Negligible

Erosion Negligible

Flood $814,334


Drought Negligible

Lightning $55,307

Wildfire Negligible

Geologic Hazards

Earthquake $5,939,000

Landslide Negligible

Land Subsidence/Sinkhole Negligible


Extreme Heat Negligible

Hailstorm $6,356

Hurricane & Tropical Storm $157,000

Severe Thunderstorm/High Wind $295,592

Tornado $1,445,532

Winter Storm & Freeze $2,485

Note: In this table, the term “Negligible” is used to indicate that no records of dollar losses for the particular hazard were recorded. This could be the case either because there were no events that caused dollar damage or because documentation of that particular type of event is not well kept.

As noted previously, all existing and future buildings and populations (including critical facilities) are vulnerable to atmospheric hazards including drought, lightning, extreme heat, hailstorm, hurricane and tropical storm, severe thunderstorm/high wind, tornado, and winter storm and freeze. Some buildings may be more vulnerable to these hazards based on other factors such as construction and building type. Table B.42 shows the critical facilities vulnerable to the hazards analyzed in this section. The table lists those assets that are determined to be exposed to each of the identified hazards (marked with an “X”).



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TABLE B.42: AT-RISK CRITICAL FACILITIES IN DESOTO COUNTY FLOOD-RELATED FIRE-RELATED GEOLOGIC WIND-RELATED

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FACILITY NAME FACILITY TYPE

DeSoto County

De Soto County Civil Defense EOC X X X X X X X X X X X X X

Hernando Fire Department Fire Station X X X X X X X X X X X X

Alphaba Cockrum Ingrams Mill Volunteer FD Fire Station X X X X X X X X X X X X

Love Fire Department Fire Station X X X X X X X X X X X X X

Hernando Fire Department Fire Station X X X X X X X X X X X X X

Eudora Fire Department Fire Station X X X X X X X X X X X X

Walls Fire Department Fire Station X X X X X X X X X X X X X

Horn Lake Fire Department Fire Station X X X X X X X X X X X X X



Nesbit Volunteer Fire Department Fire Station X X X X X X X X X X X X X

Bridgetown Fire Dept Fire Station X X X X X X X X X X X X X

Olive Branch Fire Department Fire Station X X X X X X X X X X X X X

Olive Branch Fire Department Fire Station X X X X X X X X X X X X

Fairhaven Vfd Fire Station X X X X X X X X X X X X X

Hernando Fire Department Fire Station X X X X X X X X X X X X

30 As noted previously, these facilities could be at risk to dam failure if located in an inundation area. Data was not available to conduct such an analysis. There was no local

knowledge of these facilities being at risk to dam failure. As additional data becomes available, more in-depth analysis will be conducted.



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FLOOD-RELATED FIRE-RELATED GEOLOGIC WIND-RELATED

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Lewisburg Vfd Fire Station X X X X X X X X X X X X

Southaven City Hall Fire Station X X X X X X X X X X X X X

Southaven Fire Department Station 1 Fire Station X X X X X X X X X X X X X

Southaven Fire Department Station 2 Fire Station X X X X X X X X X X X X X X



Parkwood Hlth System Medical X X X X X X X X X X X X

Methodist Olive Branch Medical X X X X X X X X X X X X X

Baptist Mem Hospital-Desoto Medical X X X X X X X X X X X X X

De Soto County Sheriff Police Station X X X X X X X X X X X X X

Hernando Police Dept Police Station X X X X X X X X X X X X X

Horn Lake Police Dept Police Station X X X X X X X X X X X X X

Horn Lake Police Substation Police Station X X X X X X X X X X X X X

Olive Branch Police Chief Police Station X X X X X X X X X X X X

Southaven Police Dept Police Station X X X X X X X X X X X X X

Southaven Police Dept East Precinct Police Station X X X X X X X X X X X X X

Hernando Middle School School X X X X X X X X X X X X X

Hernando High School School X X X X X X X X X X X X X

Hernando Elem School X X X X X X X X X X X X X



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Oak Grove Central Elementary School X X X X X X X X X X X X X

Desoto County Alternative Center School X X X X X X X X X X X X X

Hernando Hills Elem School X X X X X X X X X X X X X

Horn Lake Middle School School X X X X X X X X X X X X X

Horn Lake Elem School X X X X X X X X X X X X X

Horn Lake High School X X X X X X X X X X X X X

Shadow Oaks Elementary School School X X X X X X X X X X X X X

Horn Lake Intermediate School School X X X X X X X X X X X X X X

Pleasant Hill Elementary School X X X X X X X X X X X X X

Lewisburg Elementary School School X X X X X X X X X X X X

Olive Branch Intermediate School School X X X X X X X X X X X X X

Olive Branch Elem School X X X X X X X X X X X X

Olive Branch High School School X X X X X X X X X X X X

Olive Branch Middle School X X X X X X X X X X X X

Chickasaw Elementary School School X X X X X X X X X X X X

Center Hill Elementary School School X X X X X X X X X X X X

Lewisburg Primary School X X X X X X X X X X X X X

Lewisburg Middle School X X X X X X X X X X X X X

Center Hill Middle School X X X X X X X X X X X X X

Center Hill High School X X X X X X X X X X X X X



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Overpark Elem School X X X X X X X X X X X X X

DCS Career Tech Center- East School X X X X X X X X X X X X X

Lewisburg High School X X X X X X X X X X X X X

Southaven Elementary School X X X X X X X X X X X X X

Southaven High School School X X X X X X X X X X X X X

Hope Sullivan Elementary School School X X X X X X X X X X X X X

Southaven Middle School School X X X X X X X X X X X X X X

Desoto Central Middle School School X X X X X X X X X X X X X

Desoto Central Elementary School School X X X X X X X X X X X X X

Desoto Central High School School X X X X X X X X X X X X X

DeSoto Central Primary School X X X X X X X X X X X X X

Southaven Intermediate School X X X X X X X X X X X X X

DCS Career Tech Center- West School X X X X X X X X X X X X X

Greenbrook Elementary School School X X X X X X X X X X X X X

Walls Elementary School School X X X X X X X X X X X X

Lake Cormorant Elem School X X X X X X X X X X X X X

Lake Cormorant Middle School X X X X X X X X X X X X X

Lake Cormorant High School X X X X X X X X X X X X X



B:70

B.4 DESOTO COUNTY CAPABILITY ASSESSMENT This subsection discusses the capability of DeSoto County to implement hazard mitigation activities. More information on the purpose and methodology used to conduct the assessment can be found in Section 7: Capability Assessment.

B.4.1 Planning and Regulatory Capability Table B.43 provides a summary of the relevant local plans, ordinances, and programs already in place or under development for DeSoto County. A checkmark () indicates that the given item is currently in place and being implemented. An asterisk (*) indicates that the given item is currently being developed for future implementation. A dagger (†) indicates that the given item is administered for that municipality by the county. Each of these local plans, ordinances, and programs should be considered available mechanisms for incorporating the requirements of the MEMA District 1 Regional Hazard Mitigation Plan.

TABLE B.43: RELEVANT PLANS, ORDINANCES, AND PROGRAMS

Pla

nn

ing

Too

l/R

egu

lato

ry T

oo

l

Haz

ard

Mit

igat

ion

Pla

n

Thre

at a

nd

Haz

ard

Ide

nti

fica

tio

n a

nd

Ris

k A

sse

ssm

en

t (T

HIR

A)

Co

mp

reh

ensi

ve L

and

Use

Pla

n

Flo

od

pla

in M

anag

emen

t P

lan

/Flo

od

Mit

igat

ion

Pla

n

Op

en S

pac

e M

anag

emen

t P

lan

(P

arks

&

Rec

/Gre

enw

ay P

lan

Sto

rmw

ater

Man

agem

ent

Pla

n/O

rdin

ance

Nat

ura

l Re

sou

rce

Pro

tect

ion

Pla

n

Flo

od

Res

po

nse

Pla

n

Emer

gen

cy O

per

atio

ns

Pla

n

Emer

gen

cy M

anag

emen

t A

ccre

dit

atio

n

Pro

gram

(EM

AP

Acc

red

itat

ion

)

Co

nti

nu

ity

of

Op

erat

ion

s P

lan

Evac

uat

ion

Pla

n

Dis

aste

r R

eco

very

Pla

n

Cap

ital

Imp

rove

me

nts

Pla

n

Eco

no

mic

Dev

elo

pm

ent

Pla

n

His

tori

c P

rese

rvat

ion

Pla

n

Flo

od

Dam

age

Pre

ven

tio

n O

rdin

ance

Zon

ing

Ord

inan

ce

Sub

div

isio

n O

rdin

ance

Un

ifie

d D

evel

op

men

t O

rdin

ance

Po

st-D

isas

ter

Re

dev

elo

pm

ent/

Rec

on

stru

ctio

n

Pla

n/

Ord

inan

ce

Bu

ildin

g C

od

e

Fire

Co

de

Nat

ion

al F

loo

d In

sura

nce

Pro

gram

(N

FIP

)

NFI

P C

om

mu

nit

y R

atin

g Sy

stem

(C

RS

Pro

gram

)

DESOTO COUNTY *

Hernando † †

Horn Lake † †

Olive Branch † †

Southaven † †

Walls † †

A more detailed discussion on the county’s planning and regulatory capabilities follows.



B:71

EMERGENCY MANAGEMENT Hazard Mitigation Plan DeSoto County has previously adopted a hazard mitigation plan. The City of Hernando, City of Horn Lake, City of Olive Branch, City of Southaven, and Town of Walls were also included in this plan. Emergency Operations Plan DeSoto County maintains an emergency operations plan through its County Emergency Management Agency. The City of Southaven is the only municipality in the county that has adopted a municipal-level emergency operations plan.

GENERAL PLANNING Comprehensive Land Use Plan DeSoto County has adopted a county comprehensive plan. The City of Hernando, City of Horn Lake, City of Olive Branch, and City of Southaven have also adopted municipal-level development and comprehensive plans. Capital Improvements Plan DeSoto County has adopted a capital improvements plan. Zoning Ordinance DeSoto County, City of Hernando, City of Horn Lake, City of Olive Branch, City of Southaven, and Town of Walls have each adopted a zoning ordinance. Subdivision Ordinance DeSoto County, City of Hernando, City of Horn Lake, City of Olive Branch, City of Southaven, and Town of Walls have each adopted a subdivision ordinance. Building Codes, Permitting, and Inspections DeSoto County, City of Hernando, City of Horn Lake, City of Olive Branch, City of Southaven, and Town of Walls have all adopted a building code.

FLOODPLAIN MANAGEMENT Table B.44 provides NFIP policy and claim information for each participating jurisdiction in DeSoto County.

TABLE B.44: NFIP POLICY AND CLAIM INFORMATION

Jurisdiction

Date Joined NFIP

Current Effective Map

Date

NFIP Policies in Force

Insurance in Force

Closed Claims

Total Payments to

Date

DESOTO COUNTY† 05/03/90 05/05/14 189 $47,158,800 42 $1,138,498

Hernando 08/19/85 05/05/14 27 $7,065,700 4 $131,098

Horn Lake 05/03/90 05/05/14 200 $39,607,600 73 $1,542,756



B:72

Jurisdiction

Date Joined NFIP

Current Effective Map

Date

NFIP Policies in Force

Insurance in Force

Closed Claims

Total Payments to

Date

Olive Branch 07/02/87 05/05/14 141 $39,949,800 19 $363,077

Southaven 09/18/87 05/05/14 356 $89,696,300 78 $2,250,137

Walls 10/02/07 06/04/07 10 $1,796,900 0 $0

†Includes unincorporated areas of county only Source: NFIP Community Status information as of 8/17/2016; NFIP claims and policy information as of 6/30/2016

All jurisdictions listed above that are participants in the NFIP will continue to comply with all required provisions of the program and will work to adequately comply in the future utilizing a number of strategies. For example, the jurisdictions will coordinate with MEMA and FEMA to develop maps and regulations related to special flood hazard areas within their jurisdictional boundaries and, through a consistent monitoring process, will design and improve their floodplain management program in a way that reduces the risk of flooding to people and property. Community Rating System The City of Hernando is the only jurisdiction in DeSoto County that participates in the CRS and it has a Class 9 rating. Flood Damage Prevention Ordinance All communities participating in the NFIP are required to adopt a local flood damage prevention ordinance. DeSoto County, City of Hernando, City of Horn Lake, City of Olive Branch, City of Southaven, and Town of Walls all participate in the NFIP and have adopted flood damage prevention regulations. Floodplain Management Plan None of the jurisdictions in DeSoto County has adopted a floodplain management plan to help prevent damages associated with flooding and flood loss. However, in August 2015, the DeSoto County Board authorized the Army Corps of Engineers (under the Federal Water Resources Development Act of 1974) to assist in preparing a comprehensive flood mitigation plan. Open Space Management Plan DeSoto County has adopted a county greenways master plan. The City of Hernando has a municipal master parks plan in place. Stormwater Management Plan DeSoto County has adopted a stormwater management plan. Desoto County, City of Horn Lake, City of Olive Branch, and City of Southaven have also adopted local stormwater management ordinances.

B.4.2 Administrative and Technical Capability Table B.45 provides a summary of the capability assessment results for DeSoto County with regard to relevant staff and personnel resources. A checkmark () indicates the presence of a staff member(s) in that jurisdiction with the specified knowledge or skill. A dagger (†) indicates a county-level staff member(s) provides the specified knowledge or skill to that municipality.



B:73

TABLE B.45: RELEVANT STAFF/PERSONNEL RESOURCES

Staf

f/P

erso

nn

el R

eso

urc

e

Pla

nn

ers

wit

h k

no

wle

dge

of

lan

d

dev

elo

pm

en

t/la

nd

man

agem

ent

pra

ctic

es

Engi

ne

ers

or

pro

fess

ion

als

trai

ne

d in

con

stru

ctio

n p

ract

ice

s re

late

d t

o b

uild

ings

and

/or

infr

astr

uct

ure

Pla

nn

ers

or

engi

nee

rs w

ith

an

un

der

stan

din

g o

f n

atu

ral a

nd

/or

hu

man

-

cau

sed

haz

ard

s

Emer

gen

cy M

anag

er

Flo

od

pla

in M

anag

er

Lan

d S

urv

eyo

rs

Scie

nti

sts

fam

iliar

wit

h t

he

haz

ard

s o

f th

e

com

mu

nit

y

Staf

f w

ith

ed

uca

tio

n o

r ex

per

tise

to

ass

ess

the

com

mu

nit

y’s

vuln

erab

ility

to

haz

ard

s

Per

son

nel

ski

lled

in G

IS a

nd

/or

Haz

us

Res

ou

rce

dev

elo

pm

ent

staf

f o

r gr

ant

wri

ters

DESOTO COUNTY

Hernando † † †

Horn Lake † † †

Olive Branch † † †

Southaven † † †

Walls † † †

Credit for having a floodplain manager was given to those jurisdictions that have a flood damage prevention ordinance, and therefore an appointed floodplain administrator, regardless of whether the appointee was dedicated solely to floodplain management. Credit was given for having a scientist familiar with the hazards of the community if a jurisdiction has a Cooperative Extension Service or Soil and Water Conservation Department. Credit was also given for having staff with education or expertise to assess the community’s vulnerability to hazards if a staff member from the jurisdiction was a participant on the existing hazard mitigation plan’s planning committee.

B.4.3 Fiscal Capability Table B.46 provides a summary of the results for DeSoto County with regard to relevant fiscal resources. A checkmark () indicates that the given fiscal resource has previously been used to implement hazard mitigation actions. A dagger (†) indicates that the given fiscal resource is locally available for hazard mitigation purposes (including match funds for state and federal mitigation grant funds).



B:74

TABLE B.46: RELEVANT FISCAL RESOURCES

Fisc

al T

oo

l/R

eso

urc

e

Cap

ital

Imp

rove

me

nt

Pro

gram

min

g

Co

mm

un

ity

Dev

elo

pm

ent

Blo

ck G

ran

ts

(CD

BG

)

Spec

ial P

urp

ose

Tax

es (

or

taxi

ng

dis

tric

ts)

Gas

/Ele

ctri

c U

tilit

y Fe

es

Wat

er/S

ewer

Fee

s

Sto

rmw

ater

Uti

lity

Fee

s

Dev

elo

pm

ent

Imp

act

Fees

Gen

era

l Ob

ligat

ion

, Rev

enu

e, a

nd

/or

Spec

ial T

ax B

on

ds

Par

tner

ing

Arr

ange

men

ts o

r

Inte

rgo

vern

men

tal A

gree

me

nts

Oth

er: H

MG

P, P

DM

, HM

A, N

FIP

, SB

A,

Ho

mel

and

Sec

uri

ty G

ran

ts, a

nd

oth

er

Fed

eral

so

urc

es,

etc

.

DESOTO COUNTY † † †

Hernando † † †

Horn Lake † † †

Olive Branch † † †

Southaven † † †

Walls † † †

B.4.4 Political Capability During the months immediately following a disaster, local public opinion in DeSoto County is more likely to shift in support of hazard mitigation efforts. Table B.47 provides a summary of the results for DeSoto County with regard to political capability. A checkmark () indicates the expected degree of political support by local elected officials in terms of adopting/funding information.

TABLE B.47: LOCAL POLITICAL SUPPORT

Political Support Limited Moderate High

DESOTO COUNTY

Hernando

Horn Lake

Olive Branch



B:75

Political Support Limited Moderate High

Southaven

Walls

B.4.5 Conclusions on Local Capability Table B.48 shows the results of the capability assessment using the designed scoring methodology described in Section 7: Capability Assessment. The capability score is based solely on the information found in existing hazard mitigation plans and readily available on the jurisdictions’ government websites. This information was reviewed by all jurisdictions and each jurisdiction provided feedback on the information included in the capability assessment. Local government input was vital to identifying capabilities. According to the assessment, the average local capability score for the county and its jurisdictions is 32.5, which falls into the moderate capability ranking.

TABLE B.48: CAPABILITY ASSESSMENT RESULTS

Jurisdiction Overall Capability

Score Overall Capability

Rating

DESOTO COUNTY 44 Moderate

Hernando 34 Moderate

Horn Lake 30 Moderate

Olive Branch 31 Moderate

Southaven 33 Moderate

Walls 23 Limited

B.5 DESOTO COUNTY MITIGATION STRATEGY This subsection provides the blueprint for DeSoto County to follow in order to become less vulnerable to its identified hazards. It is based on general consensus of the Regional Hazard Mitigation Council and the findings and conclusions of the capability assessment and risk assessment. Additional Information can be found in Section 8: Mitigation Strategy and Section 9: Mitigation Action Plan.

B.5.1 Mitigation Goals DeSoto County developed six mitigation goals in coordination with the other participating MEMA District 1 Region jurisdictions. The regional mitigation goals are presented in Table B.49.



B:76

TABLE B.49: MEMA DISTRICT 1 REGIONAL MITIGATION GOALS Goal

Goal #1 Promote the development, implementation, and maintenance of local hazard mitigation plans and encourage all sectors of the community to work together to create a disaster resistant community.

Goal #2 Reduce risks and vulnerabilities of people and structures in hazard prone areas.

Goal #3 Promote education, outreach, and development programs to improve the knowledge and awareness among the citizens and industry about hazards they may face, their vulnerability to identified hazards, and hazard mitigation alternatives that can reduce their vulnerabilities.

Goal #4 Establish priorities for reducing risks to the people and their property with emphasis on long-term maximum benefits to the public rather than short-term benefit of special interests.

Goal #5 Protect the health and safety of residents through pre- and post-hazard mitigation processes.

Goal #6 Have the capability to initiate and sustain emergency response operations during and after a disaster.

B.5.2 Mitigation Action Plan The mitigation actions proposed by DeSoto County, City of Hernando, City of Horn Lake, City of Olive Branch, City of Southaven, and Town of Walls are listed in the following individual Mitigation Action Plans.



B:77

DeSoto County Mitigation Action Plan

Action #

Description Hazard(s)

Addressed Relative Priority

Lead Agency/ Department

Potential Funding Sources

Implementation Schedule

Implementation Status (2016)

Prevention

P-1

Codes and Regulations:

Adopt and implement uniform building codes, subdivision regulations, land use planning, and zoning ordinances that address new and existing building structures throughout the county.

Adopt and implement regulations and codes that address vulnerability to the hazards listed in the Hazard Mitigation Plan for existing critical infrastructure as defined in Action ES-3.

Ideas for Implementation: With assistance from NDPDD, each participating jurisdiction will review existing codes and regulations for both existing buildings and infrastructure, and for new buildings and infrastructure to determine what changes need to be made to bring local regulations into compliance.

All High

Board of Supervisors/

Board of Alderman

Local 2021

As of 2016, DeSoto County and each municipality have adopted and implemented uniform building codes, subdivision regulations, land use planning, and zoning ordinances. Implementation of these is a process that takes place at the community level as each Planning Department reviews existing codes and updates as new uniform codes are produced. DeSoto County and its associated municipalities follow the International Code Council guidelines. It is likely that the codes will need to be reviewed and potentially updated in the next 5 year period, so this action will remain in the plan. This action was amended to include existing and new critical infrastructure, as defined in Action ES-3. (Action 1 in previous plan)



B:78

Action #







P-2

Ensure that existing drainage systems (i.e., pipes, culverts, channels) are adequate and functioning properly. Ideas for Implementation: Each participating jurisdiction will appoint personnel to check local drainage system conditions and take the necessary steps to bring inadequate systems into compliance. The cost involved to bring inadequate systems into compliance will vary from one place to the next.

Flood High

County Administrator,


Board of Aldermen

General Funds, CDBG, DRA

2021

DeSoto County has established a stormwater program along with a road and drainage maintenance program. This action will remain in the plan as it is anticipated that there will be future issues with drainage systems that will require repairs/action. (Action 5 in previous plan)

P-3

Floodplain Management:

Encourage communities to participate or continue participating in the National Flood Insurance Program (NFIP).

Encourage jurisdictions to adopt and enforce floodplain management requirements, including regulating all substantially improved construction in Special Flood Hazard areas (SFHAs).

Ideas for Implementation: Promote the benefits of the NFIP program and floodplain management, and provide technical assistance in meeting program requirements including the application process.

All High


Board of Aldermen, Emergency

Management

Local 2021

All communities in DeSoto County are participants in the NFIP. This action will remain in the plan as communities will need to continue to implement floodplain management activities to maintain their participation in the NFIP. (Action 10 in previous plan)



B:79

Action #







Property Protection

PP-1

Support mitigation activities that support buyout and land acquisition programs in areas prone to flooding. Ideas for Implementation: Each participating jurisdiction will identify areas prone to flooding and develop plans to buyout or acquire the property. Flood High

Emergency Management

General Funds, MEMA, State

Homeland Security Program, USDA

Rural Dev.

2021

This action has been partly accomplished but there are many properties in the county that could be mitigated using this method. DeSoto County has participated in floodplain buyout and land acquisition to eliminate repetitive flood loss claims and will look at ways to implement future projects of this nature in the future as funding allows. (Action 7 in previous plan)

PP-2

Retrofit of critical facilities to ensure public safety in the event of a severe weather event or natural disaster.

All severe weather events

High Emergency

Management



Rural Dev.

2021

DeSoto County has begun retrofitting of key critical facilities to ensure public safety in the event of severe weather. Some projects are in the works such as safe rooms within public schools and replacement of the Emergency Operations Center. This action will remain in the plan as these projects are worked on and as the county looks to identify additional facilities that may be retrofit. (Action 8 in previous plan)



B:80

Action #







PP-3

Storm Shelters/Safe Rooms: The county and all municipalities would like to increase the number of shelters and safe rooms available to citizens in the event of severe weather events such as tornadoes, especially in areas of high or vulnerable population concentration. Ideas for Implementation:

Identify key locations for constructing storm shelters/safe rooms.

Apply for grant funding to support construction/implementation.


High Emergency

Management FEMA, MEMA,

Local 2019

New Action

Natural Resource Protection NRP-1

Structural Projects SP-1

Emergency Services

ES-1

Provide residents with adequate warning of potential floods and other meteorological events. Ideas for Implementation: Each participating jurisdiction will assess the condition of their current warning systems and upgrade where necessary. All severe

weather events

High Emergency

Management


Homeland Security Program

2018

As of 2016, DeSoto County works with the National Weather Service, broadcast media, and other emergency agencies to provide warnings of potential floods and other meteorological events. The warning system includes outdoor warning sirens, AlertFM, and NOAA weather radios. As the county looks to continue to improve public warning systems, this action will remain in place. (Action 2 in previous plan)



B:81

Action #







ES-2

Strengthen emergency services preparedness and response ability by purchasing equipment (i.e., generators and other supplies) to be used a key critical facilities around the county. Ideas for Implementation: Each participating jurisdiction will inventory current emergency supplies and identify items needed to improve response ability.

All High Emergency

Management



Rural Dev.

2020

DeSoto County has purchased equipment such as standby generators, portable generators, and trash pumps for use in maintaining critical facilities. Due to the evolving nature of this type of equipment and the fact that many improvements can still be made to improve preparedness, this action will remain in place. (Action 6 in previous plan)

ES-3

Strengthen emergency services preparedness and response ability and strengthen hazard mitigation vulnerability assessment by mapping the locations of key government or public housing structures and buildings, especially vulnerable structures, critical infrastructure, and elderly and handicapped housing. Precise data will be gathered to identify weaknesses in preparedness for all hazards listed in the Hazard Mitigation Plan. Ideas for Implementation: Each participating jurisdiction will inventory its own structures, or may use the help of NDPDD, to map structures and assess their vulnerabilities. These data will be amended to the plan.

All High Emergency

Management General Funds 2018

During this update of the hazard mitigation plan, many critical facilities/infrastructure were mapped, but there will be a need to constantly evaluate/update this data and it should be noted that not all vulnerable populations or facilities were mapped, so additional work is already needed. (Action 9 in previous plan)



B:82

Action #







Public Education and Awareness

PEA-1

Provide education opportunities for local officials to make sure they are well trained regarding natural hazards and appropriate prevention and mitigation activities. Ideas for Implementation: Elected officials in each participating jurisdiction will attend an educational program or seminar designed to increase awareness of natural hazards and ways to minimize their impact on the county.

All High Emergency

Management General Funds,

MEMA 2021

Elected officials attend and participate in educational programs to heighten their awareness of natural hazards. Due to the constant need for additional training, this action will remain in place to ensure local officials are up to date. (Action 3 in previous plan)

PEA-2

Organize and conduct a public outreach program designed to make sure that residents and business owners are aware of the potential hazards associated with their environment and the ways they can protect themselves. Ideas for Implementation: Each participating jurisdiction will coordinate outreach events to educate the public of the risks of natural hazards and ways to reduce their vulnerability to such events.

All High Emergency


MEMA 2021

The Emergency Management Agency conducts outreach training to citizens groups, and attends or participates in public ventures such as Fire Department Open House, neighborhood block parties, and other events. This action will remain in the plan as public outreach needs to continue and improve as new outreach strategies are developed and employed to reach a broader audience. (Action 4 in previous plan)



B:83

City of Hernando Mitigation Action Plan

Action #







Prevention

P-1





All High


Board of Alderman

Local 2021




B:84

Action #







P-2


Flood High



Board of Aldermen


2021


P-3





All High



Management

Local 2021




B:85

Action #







Property Protection

PP-1





Rural Dev.

2021


PP-2



High Emergency

Management



Rural Dev.

2021




B:86

Action #







PP-3





High Emergency


Local 2019

New Action



Emergency Services

ES-1


weather events

High Emergency

Management



2018




B:87

Action #







ES-2


All High Emergency

Management



Rural Dev.

2020


ES-3


All High Emergency





B:88

Action #








PEA-1


All High Emergency


MEMA 2021


PEA-2


All High Emergency


MEMA 2021




B:89

City of Horn Lake Mitigation Action Plan

Action #







Prevention

P-1





All High


Board of Alderman

Local 2021




B:90

Action #







P-2


Flood High



Board of Aldermen


2021


P-3





All High



Management

Local 2021




B:91

Action #







Property Protection

PP-1





Rural Dev.

2021


PP-2



High Emergency

Management



Rural Dev.

2021




B:92

Action #







PP-3





High Emergency


Local 2019

New Action



Emergency Services

ES-1


weather events

High Emergency

Management



2018




B:93

Action #







ES-2


All High Emergency

Management



Rural Dev.

2020


ES-3


All High Emergency





B:94

Action #








PEA-1


All High Emergency


MEMA 2021


PEA-2


All High Emergency


MEMA 2021




B:95

City of Olive Branch Mitigation Action Plan

Action #







Prevention

P-1





All High


Board of Alderman

Local 2021




B:96

Action #







P-2


Flood High



Board of Aldermen


2021


P-3





All High



Management

Local 2021




B:97

Action #







Property Protection

PP-1





Rural Dev.

2021


PP-2



High Emergency

Management



Rural Dev.

2021




B:98

Action #







PP-3





High Emergency


Local 2019

New Action



Emergency Services

ES-1


weather events

High Emergency

Management



2018




B:99

Action #







ES-2


All High Emergency

Management



Rural Dev.

2020


ES-3


All High Emergency





B:100

Action #








PEA-1


All High Emergency


MEMA 2021


PEA-2


All High Emergency


MEMA 2021




B:101

City of Southaven Mitigation Action Plan

Action #







Prevention

P-1





All High


Board of Alderman

N/A 2021




B:102

Action #







P-2


Flood High



Board of Aldermen


2021


P-3





All High



Management

N/A 2021




B:103

Action #







Property Protection

PP-1





Rural Dev.

2021


PP-2



High Emergency

Management



Rural Dev.

2021




B:104

Action #







PP-3





High Emergency


Local 2019

New Action



Emergency Services

ES-1


weather events

High Emergency

Management



2018




B:105

Action #







ES-2


All High Emergency

Management



Rural Dev.

2020


ES-3


All High Emergency





B:106

Action #








PEA-1


All High Emergency


MEMA 2021


PEA-2


All High Emergency


MEMA 2021




B:107

Town of Walls Mitigation Action Plan

Action #







Prevention

P-1





All High


Board of Alderman

Local 2021




B:108

Action #







P-2


Flood High



Board of Aldermen


2021


P-3





All High



Management

Local 2021




B:109

Action #







Property Protection

PP-1





Rural Dev.

2021


PP-2



High Emergency

Management



Rural Dev.

2021




B:110

Action #







PP-3





High Emergency


Local 2019

New Action



Emergency Services

ES-1


weather events

High Emergency

Management



2018




B:111

Action #







ES-2


All High Emergency

Management



Rural Dev.

2020


ES-3


All High Emergency





B:112

Action #








PEA-1


All High Emergency


MEMA 2021


PEA-2


All High Emergency


MEMA 2021


annex b - mema district 1 regional hazard mitigation … · 2018-09-04 · annex b: desoto county...

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