In mountainous regions, great masses of loosened snow, ice, earth, or rocks sometimes slide down the side of a mountain, destroying everything in their path. These slides are called avalanches, from the French word meaning descent. Smaller masses of snow and ice are called snowslides. An avalanche can be triggered by a loud noise such as a blast or thunder.
Avalanches frequently occur in the spring when the snow begins to melt. The most dangerous avalanches are started by strong winter winds, which cause great masses of solid snow to drop with tremendous force toward the valley below. In the summer, ice avalanches break off from high glaciers during periods of thawing and crash to lower elevations.
The Alpine region of Europe suffers more avalanches than anywhere else in the world. Deaths related to avalanches in the Alps from 1993 to 1998 totaled 504. France reported the most, with 168 fatalities. Austria had 142 deaths, Switzerland 104, and Italy 90. For a like period of time the entire United States lost 148 victims to avalanches. Unfortunately the average number of Americans killed by avalanches has more than tripled, rising from seven a year in the 1970s to twenty-four a year in the 1990s. This is mainly due to a marked increase in backcountry skiers, snowboarders, and snowmobilers. The rapidly increasing housing, condominium, and ski resort construction in the mountains causes avalanche experts to see a potential threat to human safety as more vacationers tend to move into avalanche-prone areas in the Rockies and other high mountainous parts of the United States and Canada.
Avalanches can be very destructive. Entire villages in the Alps have been destroyed by them with considerable loss of human life. Especially