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| Avalanches
are not what you think |
Noise does NOT trigger avalanches. Although the idea
is a convenient plot device in movies, it’s just
a myth that just won’t go away.
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In 90 percent of all avalanche accidents, the victim or
someone in the victim’s party triggers the slide.
Avalanches are the only natural hazard commonly triggered
by the victim. |
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Dry slab avalanches account for almost all avalanche accidents.
A dry slab avalanche is a cohesive plate of dry snow that
fractures as a unit, and then breaks apart as it slides--like
a pane of glass sliding off an inclined table. |
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A typical dry snow avalanche travels around 60-80 mph.
An avalanche reaches these speeds within five seconds
after it fractures. |
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A typical dry snow avalanche travels around 60-80 mph.
An avalanche reaches these speeds within five seconds
after it fractures. |
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Avalanches do not strike without warning. They happen
in particular places due to specific combinations of snow
and weather conditions. There are almost always obvious
signs that these conditions exist. |
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Avalanches are a daily part of life in Utah. About 10,000
avalanches occur each winter in Utah. Of these, there
are over 100 unintentional, human-triggered avalanche
incidents in which about 20 people are caught. On average,
four people die in avalanches in Utah each winter. |
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| The
Statistics |
Almost
all avalanche accidents are triggered by the victim,
who is a recreationist and very skilled at their sport;
most avalanche victims die quickly under the snow.
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Avalanche accidents rarely occur within ski areas or above
highways, because avalanche workers routinely control
avalanche hazard on such slopes with explosives. |
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In 90 percent of all avalanche accidents, the victim or
someone in the victim’s party triggers the slide.
Avalanches are the only natural hazard commonly triggered
by the victim. |
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99.9 percent of avalanche accidents occur in the backcountry—the
bowls, peaks, and slopes outside of ski areas, where there
is no avalanche control. |
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Three quarters of victims die from asphyxiation—breathing
their own carbon dioxide—and a quarter of victims
die from trauma caused by hitting trees and rocks on the
way down. Only 2 percent live long enough to die from
hypothermia. |
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Half of all completely buried avalanche victims die within
the first 25 minutes. 95 percent are dead within the first
two hours. |
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Almost all avalanche accidents occur to recreationists
who are very skilled at their sport. Despite this expertise,
their avalanche skills usually lag far behind their sport
skills. |
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Nearly twice as many snowmobilers are killed in avalanches
than any other group of recreationist. Snowmobiles can
not only go any place a skier can go, but they can cover
100 times the amount of terrain in a day as a skier, so
if any instabilities exist, snowmobilers are likely to
find them. |
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Other victims in fatal avalanche accidents include skiers,
climbers, snowboarders, snowshoers, hikers and hunters,
in that order. |
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Over 90 percent of avalanche fatalities in Utah did not
call the avalanche advisory before heading out into the
backcountry. |
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We can avoid the vast majority of avalanche accidents
with just a little bit of knowledge. |
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Almost all avalanche accidents occur to recreationists
who are very skilled at their sport. Despite this expertise,
their avalanche skills usually lag far behind their sport
skills. |
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The UAC aims
to keep people on top of the Greatest Snow on Earth
instead of buried beneath it. |
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The Forest Service Utah Avalanche Center was created in
1980 to combat the rising tide of avalanche deaths in
Utah. We give backcountry travelers critical avalanche
information that can help them make what are sometimes
life and death decisions. |
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We gather our information every day from the avalanche
professionals at ski resorts, the Utah Department of Transportation
and the helicopter skiing companies. We also have a team
of volunteer observers who call us every time they go
out. But our most important source of information comes
from our own fieldwork. We travel around in the backcountry
two to three days per week, digging holes in the snow
and examining the weak layers in the snowpack that produce
avalanches. |
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In our advisories, we tell people what kind of avalanche
activity is occurring, why it’s occurring, where
they will likely find the danger and what clues to the
hazard exist. |
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The information is available in a variety of media. We
record six avalanche hotlines, customizing them for local
calling areas in all the communities of northern Utah.
We also e-mail advisories and post them on the Internet.
Local public radio stations broadcast daily interviews
with avalanche specialists. During times of extreme danger,
we issue avalanche warnings that are broadcast on NOAA
weather radio and distributed to all media. |
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Most avalanche
accidents can be avoided with simple education and preparation.
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Call the Forest Service Utah Avalanche Center hotline
or read the advisory on the Internet for current and critical
avalanche information you will need to stay alive in backcountry
avalanche terrain. |
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Always carry avalanche rescue gear. Include an electronic
avalanche rescue beacon, a shovel and a probe. |
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Take an avalanche class or go with a guide so that you
can recognize obvious signs of danger. |
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People can learn
to recognize dangerous slopes and conditions. |
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Terrain: Slopes without thick trees and
steeper than about 30 degrees (35-45 degrees are the most
dangerous angles). |
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Weather: Recent strong wind, recent heavy
snow, recent or prolonged melting of the snowpack |
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Obvious signs: Recent avalanches, cracking
snow, collapsing snow, recent deposits of wind-drifted
snow, sinking into wet snow. |
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Backcountry
travelers can follow simple practices to reduce the
likelihood and consequences of avalanche accidents.
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Only expose one person to the danger at a time. The rest
of the party should wait in a safe place so they can perform
a rescue if needed. Snowmobilers should not ride up to
help a stuck buddy when in avalanche terrain. |
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Never travel above your partner. |
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Start on small slopes with less dangerous consequences
and work your way up to larger, more dangerous slopes
as you gather information about the stability of the snow.
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