Snow, Ice, Avalanches, and Glaciers - Mountain Geography: Physical and Human Dimensions - page 179

victim's companions. Because of the likelihood of suffocation, this approach is typic-
ally the victim's best chance of survival. Recent research suggests that over 90 percent
of fully buried avalanche victims survive the first 15 minutes, but survival probability
drops rapidly to around 30 percent after 30 minutes (Tremper 2008). The second re-
sponse category is organized as outside rescue, such as a ski patrol or search and res-
cue unit. Some responses here can mean 24 hours or longer in a backcountry situation,
so survival in these cases is unlikely unless the victim is in a vehicle or structure. The
use of cell phones to alert rescue teams and helicopters to transport them have dramat-
ically shortened response times for organized rescues in some situations.
Live avalanche rescue is greatly enhanced by prior training in the use of an electron-
ic avalanche beacon, probe poles, and shovel; these should be worn or carried by each
party member. Other new equipment like Avalungs, which allow a person to breath un-
der the snow if they are not buried so deeply that they cannot expand their chest, and
avalanche airbags, which help to keep victims on or near the snow surface, can enhance
the chances of surviving an avalanche. In addition, each member of the party should
realize that they are the victim's best hope and should not go for help until all other on-
site efforts have been exhausted or unless assured help is very close (within minutes).
Trained dogs are also very effective at locating victims (Tremper 2008).
FIGURE 4.24 Annual United States avalanche fatalities (vertical bars), and a five-year running aver-
age (line), from 1950 to 2010. Fatalities increased in the 1970s and again in the 1990s as the
numbers of people recreating in the backcountry increased. (Data courtesy Colorado Avalanche
Information Center. Graph produced by L. R. Dexter from CAIC data.)
Avalanche Forecasting and Mitigation
FORECASTING AVALANCHES
The safest way to deal with avalanches is to avoid them, and this is possible only by
avoiding all snow-covered avalanche terrain. This will never occur so long as people
wish to live in, play in, and travel through mountains in the winter. Therefore, reducing
avalanche accidents relies on avoiding avalanche terrain during times of unstable snow-