avalanche avoidance and rescue

Avalanche Avoidance and RescueAvalanche Avoidance and Rescue

Outline

• Who’s at risk

• What causes avalanches

• Companion/beacon rescue

• Avalanche avoidance

• Types of avalanches

• Details about the Unit’s DTS Tracker and its use

• New user groups– Snowboarders – Snowmobilers

• Open gate policies• Media• New technologies

– Snowboards/splitboards– Alpine touring gear– Telemark gear (plastic and fat)– Snow safety equipment– Powerful snowmobiles

Winter mountain recreation hasexploded in recent years

0 10 20 30 40 50 60 70

snowmobilers

b.c. skiers

climbers

lift skiers (o.b.)

b.c. snowboarders

misc. recreation

snowboarders (o.b.)

hikers

snowshoers

lift skiers (l.a.)

ski patrolers

motorists/hwy workers

residents

others at work

Source: AAAU.S. Avalanche fatalities by activity, 1990 to 2002

About 97% of people killed inavalanches die while playing

Recreationists are at risk because they don’t understand the causes of avalanches

Almost all fatal avalanchesare slab avalanches

Point release (loose snow) avalanches are more easily predicted and usually less dangerous

If you understand the cause ofavalanches you can avoid them

• Human Factors

• Weather

• Snowpack

• Terrain

• New snow adds weight (stress) to the snowpack• New snow takes time to bond to layer underneath

Most avalanches occur during and immediately after storms...

Temperature, elevation and aspect (orientation) all affect snow stability

• You can have stability at one elevation but as you climb or descend the snow profile can change

• Similarly, a slope at one aspect can be safe but at a slightly different aspect can be very unstable

• Rapidly warming temperatures can weaken the snowpack

60˚

45˚

30˚

15˚

0˚

The majority of avalanches occuron slopes between 30˚ and 45˚

28˚

33˚

The majority of avalanches occuron slopes between 30˚and 45˚

• Most slabs release on the bulge of convex slopes

• Slabs can be triggered from above and below the slope

Concavity

Convexity

Slope shape also needs to be considered

Dense trees can act as “anchors”and points of safety

A weak snowpack usually consists of a strong layer overlying a weak layer

• Learn to evaluate the snowpack

• There’s no substitute for on-snow avalanche instruction

• Take a Level I avalanche course

• Practice

Some slab avalanches are huge

Most killer avalanches aresmall and human triggered

1. Skier

2. Slope convexity

3. Roughly 30 degrees

4. Debris slid into concavity

Know before you go!

• Call local avalanche forecast center

• Know the snowpack history

• Talk to others who have been out

• Talk to ski patrol

Human factors

• Attitude : people sometimes ignore danger signs due to pride, ego and ambition

• Time : weekend warrior syndrome

• Blue Sky : sunny weather sometimes draws people too soon after a storm

• Herding Instinct : people think less in large groups

With good back country habits, youcan avoid avalanche danger

1. Expose only one person at a time 1. Expose only one person at a time

2. Get out of the way at the bottom2. Get out of the way at the bottom

3. Never cross above your partner3. Never cross above your partner

4. Have an escape route planned4. Have an escape route planned

5. Remove pole straps and safety straps5. Remove pole straps and safety straps

6. Travel in the same route when possible6. Travel in the same route when possible

7. Keep your partner in sight7. Keep your partner in sight

8. Travel to points of safety8. Travel to points of safety

Consider the terrainconsequences in route selection

Will I go over a cliff?Will I go over a cliff?Will I get crushed by trees?Will I get crushed by trees?Will I get cut by sharp rocks?Will I get cut by sharp rocks?Will I be buried?Will I be buried?

Good route selection can limit exposure to hazardous terrain

Is there a better alternative?

Without exposure to the steep slopes

Good route selection can limit exposure to hazardous terrain

Asphyxiation is the causeof most avalanche fatalities

Asphyxiation75%

Trauma25%

Source: AAA

0

10

2030

40

50

60

7080

90

100

0 15 30 45 60 75 90 105 120 135 150

Time in minutes

RecoveredAlive (%)

Source: AAA(422 completely buried victims)

If recovered within 15 minutes,chances of survival are almost 92%

At 35 minutes, survival rate drops to 37%

After that, the success rate is extremely low.1

…but if you get to them fastenough, you can save them

Source: CAIC

Only a member of your party or a companion will likely save your life

white(68%) cover(15%)

Search Method Search Time Success Rate

Beacon <15 min 98% 1 Person

Search Dog

30 min 90% 1 Trained Dog

Coarse Probe

4 hours 70% 20 Person Probe Line

Fine Probe

16-20 hours 100% 20 Person Probe Line

Source: AAASearch times in 100mx100m area

…and most likely only if youhave an avalanche transceiver

If an avalanche occurs

Victim

• If caught, yell so other people see you. Then close your mouth.• If you can grab a tree or dig into the slope, do it.• Discard gear like skis and poles.• Fight with all of your effort, try to stay on the surface.• As the snow slows, try to thrust a hand upward above the snow surface.• Before the snow stops, try to clear an air space in front of your face.• If buried, do not panic! Stay calm and try to relax.

If an avalanche occurs

Rescuer(s)

• Watch the victim(s) as they are carried down the slope. Look for “last seen point.”• Make sure it is safe to begin a search.• Organize the search party.• Mark the area where the victim was last seen and begin search here. Look for any clues.• Begin beacon search• When victim is located, confirm depth and location with probe dig fast but carefully.

1. Avalanche beacon follows electronic signal to buried victim

2. Probe verifies depth and location of buried victim

3. Shovel removes snow

What do you need for a rescue?

distance

sending unit

receiving unit

Signal strength depends upon distance

Colorado Avalanche Information Center

volume

Signal strength depends upon orientation

Maximum


Minimum

Signal strength depends upon orientation


Coarse Search>40m

Fine Search40-3m

Pinpoint Search

<3m

Objective: Detectstrong signal

Objective: Get close to buried transmitter(about 3 meters)

Objective: Locate strongest signal, minimize probe and digging area

There are three phases of a transceiver search

Standard coarse search strip is 20 meters

• Effective range for most modern transceivers: 10-15 meters

• This translates to a strip width of 20-30 meters

Grid Tangent Flux

Fine search techniques

Pinpoint search – bracket or line

Coarse search

Signal picked up here, fine search

begins

Pinpoint search

The three search phases would looksomething like this for a single searcher:

1. Coarse search

2. Fine search

3. Pinpoint search

What about two searchers?

1. Coarse

2. Fine

3. Pinpoint

Probe and shovel!

What about a last seen point?

Last seen point

Search begins at star

Eliminates this areafor searching

Fracture

Debris area

Victims

Six people skiing

Last seen point, search begins here

Four rescuers and two victims

The four searchers will begin their search at the last seen point. Two will pinpoint while the other two probe and

prepare to shovel.

Basics Specifications of DTS Tracker Beacon• Frequency 457 kHz• Three AAA batteries• 250 hours in transmit, 50 hours in

search• Receive range up to 50 meters• Normal effective range is 10 meter

radius• Normal search mode window is 180°• Special search mode widow is 75°• Minimum temperature range at 66%

battery is -10° C (14° F) for transmit and -20° C(-4° F) for search

Basics of Operating DTS Tracker Beacon• Black strap is the waist strap, red is

shoulder• Can unbuckle beacon to extend it without

removing waist strap• During start up, should have 95 to 99%

battery display• After start up, enters transmit (tr) mode

and side light flashes• To enter search mode, hold

Search/Transmit Button down until display changes to “SE” and beacon beeps three times

• Directional LED points along the flux line• Distance along flux line is in meters• To go back to transmit mode, push the

Search/Transmit Button

Options for DTS Tracker Beacon

• Auto-Revert System– Hold down Options Button while

starting– “Ar” will be shown in display– After 5 minutes in search mode,

beacon will sound 10 second alarm then switch to transmit mode unless Search/Transmit Button is pushed


• Special Mode– While in search mode, hold down

Options Button until “SP” is displayed– Normal search only indicates the

strongest signal within about 10 meters.

– Special search indicates all signals within search window no matter what strength

– Search window is reduced from 180° to 75°


• Turning Off The Vastly Annoying Beep– To stop the beeping sounds in search

mode, push the Options Button until “L0” is displayed

– To turn the sound back on, push the Options Button until “L1” is displayed

Single Victim Search With DTS Tracker

• Turn all beacons to search• Start at last seen location and use

coarse search pattern to find a signal• Look for surface clues while moving• Move beacon in slow horizontal and

vertical pattern to help find a signal• Once a signal is located, mark the

location and follow the flux line indicated with the top LED and decreasing distance

• Move rapidly to 10 meters then start moving slowly to around 3 meters

• Once at about 3 meters, start to move very slowly and use pinpoint bracket or line method to locate closest point for probing

• Hold beacon right on snow surface• Ignore spike readings and LED

fluctuation when this close

Multiple Victims Using Normal Search Mode• The search is the same up to locating the

first signal• Follow the LED towards the closest

beacon and when significantly closer to one beacon and within 10 meters, the Tracker will lock onto one beacon and mask out the others

• When dug out, turn off the first beacon• If first beacon can’t be turned off but you

have an idea where the next beacon is, head towards it until signal is isolated

• If no idea where next beacon is, step back three paces and slowly walk a circle around the first beacon. If required, step back two more times and repeat the circle, then return to first signal location if required.

• Once a signal is acquired when walking the circle, start towards it to isolate it

Multiple Victims Using Special Search Mode• The search is the same up to locating the

first beacon and beacon can’t be turned off

• With Tracker at lowest distance reading and center LED on, switch to special mode

• Rotate the DTS Tracker – do not sweep it – slowly to find other signals

• If no signal is detected, try standing up and rotating the DTS Tracker at chest height

• If no signal is detected, step back three paces and try rotating the Tracker again

• Once a signal is isolated note the distance and move rapidly about ¾ of the distance then switch back to normal search mode

• Finish covering the entire avalanche area using a coarse search pattern to make sure all beacons are located

Tips for Three or More Victims

• Three or more beacons, especially if close together, are very hard to separate out

• Try decreasing coarse search overlap to 5 meters instead of 20

• It is especially important to enter special search mode as close as possible to a beacon to help distinguish the distance to other beacons

• Avoid going into special search mode over a beacon’s spike area

• Pinpointing on a line can be very difficult if many beacon’s flux lines are all converging in one area, try the bracket method instead

avalanche avoidance and rescue

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