Avalanche

Definition

Rapid flow of snow (snow avalanche), debris (debris avalanche), or rock (rockslide avalanche) downslope when the force of the material exceeds its strength. Avalanches accelerate rapidly and increase in their mass and volume under the influence of gravity.

Context

Snow avalanches occur spontaneously when the snow load increases beyond its strength, coupled with a trigger such as melting, rain, earthquake, landslide, and more commonly in recent years human activity including skiers, hikers, snowmobiles, etc.

Snow avalanches pose a considerable threat to recreation, property, resources, energy/communication corridors, and human lives across the world in all sloped and cold climate environments that are prone to snow accumulation and fluctuating temperatures. Globally, an estimated 250 individuals die in avalanches per year, including about 14 deaths per year in Canada, 28 deaths per year in the USA and 103 deaths per year in the European Alps. The number of fatalities has...