Windstorms of the Pacific

Northwest

Cliff Mass

Atmospheric Sciences

University of Washington

Many Believe that Northwest Weather is Benign

But beneath the velvet softness of region’s fog and gentle rain, Mediterranean summers, and mild temperatures lurks another reality… the infrequent occurrence of some of the most damaging storms on the planet.

January 29, 1921

North Head,WA LighthouseAlso a co-located Navy wireless station

Circa 1912

North HeadLight

The Unexpected• The Weather Bureau believed a storm was

approaching the coast, and at 8 AM small craft warnings were posted.

• Pressure fell rapidly at North Head until 2 PM, after which it steadied. Winds were from the east between 20 and 30 mph. To the weather observer (Mr. Hill), the worst appeared to be over.

• At 2:40 PM the Mr. Hill and his wife left for the town of Ilwaco to pick up mail and supplies… a trip that usually takes about an hour.

•Returning home around 3:15 PM they traveled a road though a dense forest of spruce and hemlock.

•Very suddenly, the wind picked up to hurricane force and beyond…

Ilwaco

1921 Windstorm Account: Mr. Mills, U.S. Weather Bureau North Head Observer

“On the return trip, a telephone pole across the roadway brought the car to a stop, and a short distance beyond the pole an immense spruce tree lay across the road. We left the machine and started to run down the road toward a space in the forest where the timber was lighter.

The southeast wind roared through the forest, the falling trees crashed to the ground in every direction from where we stood. Many were broken off where their diameter was as much as 4 feet. A giant spruce fell across the roadway burying itself within 10 feet of where we stood. Tree tops broke off and sailed through the air, some of the trees fell with a crash, others toppled over slowly as their roots were torn from the earth. In a few minutes there were but two trees standing that were dangerous to us and we watched every movement of their large trunks.

The wind shifted from the southeast to the south and the velocity decreased to probably 100 mph or it may have been as low as 90 mph. Shortly after 3:50 p.m. we started toward North Head. We climbed over fallen trunks, crawled under others, and pushed our way through tangled masses of tops that lined the roadway. We supposed that all the houses at North Head had been leveled and the wireless station demolished for we knew that the storm was the most severe that had occurred in the vicinity of the mouth of the Columbia with the last 200 years."

1921 Historical PhotographOf Tree Blow-Down

An Extraordinary Event• Hurricane-Force Winds Struck the Entire

Washington Coast – At North Head sustained (5 minute average)

winds reached 126 mph, with a maximum one-minute wind of 150 mph before the sensor failed.

– At Tatoosh Island, 150 miles to the north, winds reached 110 mph.

– At Astoria, on the south side of the Columbia, there were unofficial reports of gusts to 130 mph.

An Extraordinary Event

It was estimated that 80% of the mature timber near North Head was razed during this storm and 7-8 BILLION board feet of timber was downed over coastal Washington– eight times that blown down by Mt. St. Helens, and roughly the entire current annual harvest for the entire Pacific Northwest today.

As a result, this event has become known as the “The Olympic Blowdown Storm”

In some areas over 40% of the trees were blown down

And Even More• The North Head wireless tower was demolished and all roofs in the

vicinity were lifted from their structures. • At the nearby town of Ilwaco, dozens of boats were torn from their

moorings and dashed to pieces on beach bulkheads. Nearly all roads in the area were impassable.

• A canvas-back duck was thrown through a 1-inch glass plate window in the nearby town of Chinook.

• An entire herd of 200 elk was killed by falling timber.• Power and telephone lines are downed over western Washington.• In Seattle's Elliott Bay twenty one barges broke their mooring lines and

were driven into Puget Sound by 50- 70 mph winds, while on land a number of greenhouses were destroyed and several dozen fires were ignited.

The 1921 Storm Track

Courtesy of Wolf Read

The Great Northwest Windstorms

• The 1921 storm was one of the great windstorms of the Pacific Northwest…but by no means the most intense.

• This talk will describe the nature of these storms, review some of the major events, and describe our progress in forecasting their development.

Windstorm 101

Most Northwest Windstorms are Produced by Midlatitude Cyclones

• A cyclone is an area of low pressure around which air circulates in a counterclockwise direction (in the northern hemisphere)

Midlatitude Cyclones

• The lower the central pressure the stronger the winds. Typical winter low 990-1000 mb.

• mb --millibar is a unit of pressure. 1013 mb is equivalent to 29.92 inches--average sea level pressure

• Usually associated with areas of large changes in temperature--- fronts.

• The energy source of these storms are the temperature changes between relatively warm air from the south and cooler air from the north.

• Dominate north of approximately 30N

Weather Satellites Show These Storms As Cloud Swirls

Most Major Northwest Windstorms Are Associated with Lows that Follow a SW to NE Track

Western WA Storms

In Contrast: Tropical Cyclones• Also low pressure centers with air rotating around

counterclockwise north of the equator.• Range in intensity from tropical depressions to hurricanes.• No fronts or temperature contrasts• Associated with convection…thunderstorms• Their energy source is the heat and moisture of warm tropical

oceans. Need water temperatures greater than 80F.• Thus, they weaken rapidly over land or over cooler water.• With cool water offshore of the Northwest coast, tropical

cyclones and hurricanes do not reach our shores.

Tropical Cyclones

Hurricane: A tropical system in which the maximum sustained surface wind is 64 knots (74 mph) or greater.

The Saffir-Simpson Hurricane ScaleNote that 1-minute average winds are used below.

• Category One:Winds 74-95 mph, above 980 mb

• Category Two:Winds 96-110 mph, 965-980 mb

• Category Three:Winds 111-130 mph , 945-965 mb

• Category Four:Winds 131-155 mph, 920-945 mb

• Category Five:Winds greater than 155 mph, below 920 mb

• Category Six: Only in the imagination of TV scriptwriters

The Hybrids

• Occasionally, tropical cyclones move northward and get transformed into midlatitude cyclones

• Some of the strongest Northwest windstorms had such an origin… such as the 1962 Columbus Day Storm

Other Differences

• Midlatitude storms do not weaken as quickly over land as tropical storms.

• Midlatitude storms generally move much faster.

• Midlatitude storms are generally larger in size.

• Midlatitude storms in our neighborhood have a forced multiplier… big trees.

Force Multiplier

ProfessorBob Houze’shome after a minor windstorm: he was standing outside and had to jump for his life!

Easter Sunday, April 97

History

Native Americans knew about NW windstorms and had several legends regarding their origin.

The Thunderbird

Early Settlers • As European settlers moved into the

Northwest during the later half of the nineteenth century, they also learned that Northwest windstorms were a force to be reckoned with.

• Seattle pioneer Arthur Denny noted that "the heaviest windstorm since the settlement of the country" occurred on 16 November 1875 and was "a strong gale, which threw down considerable timber and overturned light structures, such as sheds and outbuildings.”

Arthur Denny

Seattle

January 9, 1880• Regarded by the Portland Oregonian as "the most violent storm ...since its

occupation by white men", the cyclone swept through northern Oregon and southern Washington toppling thousands of trees, many 5-8 ft in diameter.

• Sustained wind of 60 mph with gusts to 73 mph begin in Portland during the early afternoon, with stronger winds to the south, demolishing and unroofing many buildings, uprooting trees, felling telegraph wires, and killing one person.

• Scores of buildings throughout the Willamette Valley were destroyed and hundreds more, including large public buildings, were damaged. Part of the roof of the Oregon State Capital in Salem was blown off, allowing snow to accumulate inside the building.

January 9, 1880• Rail traffic was halted in most of northwest Oregon,

virtually all fences in the Willamette Valley that were aligned east-west were downed, and every barn near the coastal town of Newport, Oregon was destroyed.

• Wind gusts on the coast were estimated to reach 138 mph. At Coos Bay, a 3-masted schooner dragged its anchor, was blown onto the beach, and broke in two.

• Extraordinary deep low, with pressure falling to 955 mb (28.20 inches of mercury)

The 1880 StormHad BothWind and Snow

Courtesy of Wolf Read

"Not even among the traditions of the native Indian inhabitants of the country is there a record of a tempest so wild and furious or so disastrous and terrible in its results... The scene … was grand and terrible. The creaking of signs and buildings, the crash of falling awnings, the rumbling of tin roofs, the whistling chimes of electric wires, and above all and louder than all the fierce rage and roar of the tornado, united in a fearful and terrifying chorus. Men hurried hither and thither, eager, uncertain and fearful, women with white scared faces peered from the windows of their homes, dreading to remain yet knowing not whether to fly for safety, little children from the schools, ran homeward with frightened haste, horses snorted in helpless fear, and even the dogs were affected with the universal terror."

Description of the 1880 Storm by the Portland Oregonian

October 21, 1934• Wind gusts of 60-70 mph hit the interior of western

Oregon and Washington, with higher winds on the coast, including an 87 mph gust at North Head. Winds gusted to 70 mph at Seattle's Boeing Field and 83 mph in Tacoma.

• The storm removed roofs, overturned fishing boats, and lifted a hanger at Boeing Field off the ground that fell upon and destroyed four aircraft. Large swaths of forest were downed and waves on Puget Sound and in the Strait of Juan de Fuca reached extraordinary heights of 20 ft.

•Loss of power and telephone lines throughout western Washington, as well as numerous fires. Large display signs were ripped from buildings across the city, and dozens of buildings collapsed as a result of the strong winds. •Twenty-two people in Washington and Oregon lost their lives due to the storm.. •On the Seattle waterfront, the Pacific liner President Madison became unmoored, hit and sunk two other ships, and then smashed into a dock before coming to rest. •The smokestack of the central heating plant at the Church of the Immaculate in Seattle toppled and crashed through the dome of the sanctuary, from which parishioners had left only ten minutes before.

The Most Extreme Northwest Windstorm: The Columbus Day Windstorm of 12 October 1962

The Big One• The Columbus Day Storm was the most damaging windstorm to strike the

Pacific Northwest in 150 years.• An extensive area, stretching from northern California to southern British

Columbia experienced hurricane-force winds, massive treefalls, and power outages.

• In Oregon and Washington, 46 died and 317 required hospitalization as a result of the storm.

• Fifteen billion board feet of timber worth 750 million $ were downed, 53,000 homes were damaged, thousands of utility poles were toppled, part of the roof of Portland’s Multnomah stadium was torn off, and the twin 520 ft steel towers that carried the main power lines of Portland were crumpled.

• At the height of the storm approximately one million homes were without power in the two states, and total damage was conservatively estimated at a quarter of a billion (1962) dollars.

Columbus Day 1962: At Cape Blanco there were 150 mph with gusts to 179! Strongest winds on bluffs and windward slopes of coastal orography

Columbus Day 1962• Over coastal regions and the offshore waters the winds gusted

well over 100 mph, with 60-90 mph gusts over the western interiors of Oregon and Washington.

• At the Naselle radar site in the coastal mountains of southwest Washington gusts reached 160 mph, and a 131 mph gust was observed at Oregon's Mount Hebo Air Force Station.

• Away from the coast, winds gusted to 116 mph at Portland's Morrison Street Bridge, 90 mph in Salem OR, 100 mph at Renton WA, 80 mph at Whidbey Island Naval Air Station, 80 mph at Paine Field, 113 mph in Bellingham, 88 mph in Tacoma, 89 mph at Toledo WA, and 83 mph at West Point in Seattle.

• Even in California fierce winds were observed, with sustained winds of 68 mph in Red Bluff, in the Central Valley, and gusts of 120 mph at Mt. Tamalpais, just north of California.

Max Winds (mph)

Columbus Day Storm 1962

Began as Typhoon Frieda and then moved northward and transformed into a midlatitude cyclone.

InaugurationDayStormJanuary 20,1993

The first major windstorm to be highly skillfully forecast….But the media and public were not paying attention!

Inauguration Day Storm• Probably the second most damaging storm during the past

50 years (with the Columbus Day Storm being number one)

• Winds of over 100 mph were observed at exposed sites in the coastal mountains and the Cascades, with speeds exceeding 80 mph along the coast and in the interior of western Washington.

• In Washington State six people died, approximately 870,000 customers lost power, 79 homes and 4 apartment buildings were destroyed, 581 dwellings sustained major damage, and insured damage was estimated at 159 million.

• Along the Oregon coast, winds gusted to 86 mph at Cape Blanco and 84 mph at Arch Cape, with unofficial reports of gusts in excess of 100 mph over northwest Oregon, where massive treefalls occurred in the coastal mountains..

• As the storm moved northward along the Washington coast, winds gusted to 98 mph at Cape Disappointment along the northern terminus of the Columbia River, 94 mph at the Hood Canal Bridge, 75 mph at Alki Point, 80 mph at Enunclaw near the Cascade foothills, and a record 88 mph on the roof of the Atmospheric Sciences building at the University of Washington (Seattle). The 64 mph gust at Seattle-Tacoma Airport was the second strongest in 50 years (the record was 67 mph during the 14 November 1981 storm).

• Near the Cascade crest, winds exceeded 100 mph several times over a two-hour period at Stampede Pass and reached 116 mph at the Alpental ski area in Snoqualmie Pass.

• For the first time ever, both floating bridges across Lake Washington were closed, as was the Tacoma Narrows suspension bridge.

December 12, 1995

• Hurricane-force gusts and substantial damage covered an extraordinarily large area from San Francisco Bay to southern British Columbia, resulting in five fatalities and over 200 millions dollars damage.

• Early in the day, the storm struck northern California with gusts of 103 mph at San Francisco, 75 mph at Eureka, and 75 mph in Oakland, resulting in numerous tree falls and three deaths. In Oregon, winds at Sea Lion Caves near Florence reached 119 mph before the anemometer failed, at North Bend winds gusted to 86 mph, Newport winds attained 107 mph, and both Cape Blanco and Astoria had maximum winds that just exceeded 100 mph.

•This was one of the deepest low pressure centers ever observed over the Northwest. •Sea level pressure at Astoria dropped to 28.51 inches (965 mb), an all-time record low for that site. •Seattle experienced its all-time record low pressure (970 mb, 28.65 mb). •And there were many more pressure records!

• Over western Washington sustained winds reached 30-50 mph, with gusts of 50-80 mph. North Bend and Seattle experienced maximum gusts of 78 mph and 59 mph, respectively

• Over the waters of Puget Sound the winds were greatly enhanced compared to land: a ship just outside of Elliott Bay reported sustained winds of 60-70 mph with gusts to 90 mph, the ferry terminal at Mukilteo reported sustained winds of 60-70 mph with a gust to 86 mph, and gusts attained 76 mph on the Hood Canal Bridge.

• Approximately 400,000 homes lost power in western Washington, with nearly complete blackouts on Bainbridge, Vashon, and Mercer Islands. To the south, 205,000 customers lost power in Oregon while in northern California the total was 714,000.

An Excellent Forecast

And the media went wild!

Dec. 11

And I have mentioned only a few of the major storms….

The January 29, 1921 Olympic BlowdownThe Classic Sou'wester of December 21, 1940The Major Sou'wester of December 4, 1945The Double Windstorms of October 26-27, 1950The Double Windstorms of December 21-22, 1955The Spring Gale of April 14, 1957The Columbus Day "Big Blow" of 1962The Big Sou'wester of March 26, 1971The Double Windstorms of November 13-15, 1981The Strong Gale of December 21, 1982The Surprise Gale of March 16, 1984The Major Windstorm of December 12, 1995The New Year's Day Storm of January 1, 1997The Windstorm of January 16, 2000The Storms of December 14-16, 2002Kitsap Blowdown of February 13, 1979:The Thanksgiving Day Storm of 1983The Gale of January 16-17, 1986The Devastating Inaugural Day Storm of January 20, 1993The Underachieving Cyclone of January 18, 1996The Major Windstorm of March 2-3, 1999

The Storm King of January 9, 1880The Springtime Gale of March 27, 1963The Gale of February 5, 1965: Storm King ReduxThe October 2, 1967 Storm King "Jr."The Sudden Windstorm of March 1, 1974The Intense Cyclone of November 9-10, 1975The Sudden Blast of January 10-11, 1988The November 15, 1994 South Valley WindstormThe February 7, 2002 South Valley SurpriseThe December 16, 2002 South Valley StormThe January 1, 2004 Cyclone: Snowstorm and Blizzard StormsThe Major Windstorm of October 21, 1934The Intense Spring Gale of April 23, 1943The Strong Storm of January 15, 1951The Major Windstorm of December 4, 1951The Intense Cyclone of November 3, 1958The Windstorm of December 20, 1961The Mid-Spring Gale of April 27, 1962The Powerful Windstorm of January 19, 1964On the Track of '58: The Windstorm of December 15, 1977

Local Hurricanes

• Northwest terrain can result in the winds accelerating locally to extraordinary speeds—

• Often accompanies major Northwest windstorms associated with midlatitude cyclones.

Feb. 13, 1979: Winds over 100 kts destroyed the Hood Canal Bridge Cost to replace: over 100 million dollars

February 131979: The Hood CanalStorm

Massive TreefallsAccompaniedThe Storm-- particularly near the bridge

Enumclaw Windstorms

Enumclaw

• To the west of a weakness in the Cascades, Enumclaw frequently gets hurricane-force easterly winds…. particularly before major windstorms that produce large pressure differences across the mountains and strong winds from east at crest level.

• Thus, Enumclaw can get two windstorms, while the rest of western Washington enjoys only one.

Enumclaw: “Place of Evil Spirits”

The GreatestEnumclaw Windstorm of the LastCentury: Dec. 24, 1983

Multiply byAbout 2.3 to Get mph.

118+ mph

Our Storms are More Perfect Than Theirs

•The media and the eastern U.S. meteorological establishment have suggested that eastern U.S. midlatitude cyclones are the strongest.

• The Perfect Storm of October 1991

• The “Storm of the Century” of March 1993

•The truth is that the great Northwest windstorms have been far more intense than all eastern U.S. midlatitude cyclones and are only exceeded by Category 4 or 5 hurricanes.

The Not So “Perfect Storm”

Strong But Many NW Storms Eclipse It

• The “Perfect Storm” reached peak intensity of 972 mb and maximum sustained winds of 60 knots at 1200 UTC on October 30, 1991 when it was located about 340 n mi south of Halifax, Nova Scotia

• In New England on October 30-31, peak gusts included: 78 mph at Chatham NWS, 74 mph at Thatcher Island, 68 mph at Marblehead, 64 mph at Blue Hill Observatory (all in Massachusetts) and 63 mph at Newport, RI.

Forecasting Northwest Windstorms

Forecasting NW Windstorms• Prior to the 1980’s major windstorms were generally

poorly forecast.• By the early 1990s weather forecast models had

considerable improved and there was a greatly increased volume of observations over the oceans from weather satellites and aircraft winds.

• The result: weather forecasters started to accurately forecast many of the major windstorms, such as the Inauguration Day Storm (Jan. 20 1993) and the December 12, 1995 event.

• But major forecast failures still occur, particularly for the medium-level windstorms.

February 7, 2002• On the morning of 7

February 2002 an intense low center moved into the central Oregon coast, with absolutely no warnings by the National Weather Service.

• Produced strong winds with gusts exceeding 70 mph

Maximum WindSpeeds (mph)

The result: massive tree

falls and damage

Why was this forecast so poor?

• Failure of computer forecast models associated with lack of data over the Pacific.

• Virtually no coastal radar coverage so last-minute warnings were not possible.

ETA

48-hr Computer Forecast Valid 00 UTC 8 February 2001

Dashed-observed, solid-forecast

Low

Low

Windstorm Forecasts Should Continue to Improve

• More and better data over the Pacific from weather satellites and other sources.

• Better computer models and data assimilation.

Satellite Winds

Unmanned Aircraft

Driftsonde

But We Still Have Our Meteorological Achilles Heel

•The Northwest has the worst coastal weather radar coverage in the nation.•Often can’t see the details of weather features before they make landfall. Seriously impacts short-term forecasts, including windstorms. •If the computer models are wrong, a coastal radar would allow National Weather Service forecasters to give crucial 0-6 hr warnings.

Lack of a Coastal Weather Radar

NWS Doppler RadarCoverage

NoCoverage

In contrast..

• The complete coastal radar coverage over the eastern U.S. allows them to follow major storms… such as hurricanes… as they approach the coast and provide last minute warnings.

• The Northwest lacks such protection.

Hurricane Hugo Approaching the Atlantic Coast

With Two New Radars

•At least one, and hopefully two coastal weather radars are needed.•Cost about $4 million each.•Could save millions of dollars for a single storm.•Contact your Senators and Congressmen/women!

It’s a lot of money but consider….

The UW is going to spend $8 million on upgrades to its golf driving range!

Major Windstorm This Year?

El Nino and Major Windstorms•Major windstorms appear to avoid El Nino and La Nino years•Implication: We may escape this year.

QUESTIONS?

Northwest Weather = Terrain + Ocean Influence

SEVERESevere Risk of Windstorm

HIGHHigh Risk of Windstorm

ELEVATEDSignificant Risk of Windstorm

GUARDEDGeneral Risk of Windstorm

LOWLow Risk of Windstorm

Homeland Weather

The END