AVALANCHE INJURIES - Medicine for Mountaineering and Other Wilderness Activities - page 449

CHAPTER 30
AVALANCHE INJURIES
Colin K. Grissom, M.D.
Martin I. Radwin, M.D.
Principal Contributors
Avalanches cause a significant number of deaths among skiers, snowboarders, skimobilers,
snowshoers, and hikers. According to the Colorado Avalanche Information Center, ava-
lancheshavekilledanaverageoftwenty-fivepeopleayearintheUnitedStatesoverthelast
ten winters. Over the last three years, thirty-eight snowmobilers, twenty-two backcountry
skiers, nine in-bounds skiers, eight snowshoers and hikers, and six snowboarders have been
killed by avalanches. In Canada from 1984 to 2005, 204 avalanche deaths occurred. More
avalanchedeathsoccureveryyearintheEuropeanAlps,althoughmanyofthedeathsinthat
area stem from avalanches that enter villages.
AVALANCHE MORTALITY
Asphyxiation is the most common cause of death during avalanche burial. About 75
percent of avalanche deaths are the result of asphyxiation, about 25 percent are caused by
trauma, and very few result from hypothermia. Because asphyxiation occurs rapidly during
avalanche burial, time to extrication is a major determinant of survival. Individuals fully
buried in an avalanche have a greater than 90 percent chance of survival if extricated within
fifteen minutes, but only 30 percent after about thirtyfive minutes, emphasizing the need for
companion rescue at the avalanche site. Survival beyond thirty minutes of burial requires an
adequate air pocket for breathing, and if the air pocket is large enough, buried individuals
may survive for hours and develop severe hypothermia.
AVALANCHE SURVIVAL PROBABILITY
Because death during avalanche burial most commonly occurs from asphyxiation within
the first fifteen to thirty-five minutes, rapid access to the airway is the most important de-
terminant of survival. Other factors that influence survival include burial depth, exposed
body parts or attached objects, and ability to self-rescue in a partial burial. If people buried
by avalanches are unable to extricate themselves, then the greatest chance of survival rests
with companion rescue experienced with an avalanche transceiver, a probe, and a shovel
(after a hasty search for surface clues). Organized rescue teams usually arrive on the scene
after thirty-five minutes have elapsed, and chances of survival are markedly reduced.