An avalanche is a mass of snow sliding down a mountainside. Avalanches are also called snowslides; there is no difference in these terms. An avalanche occurs when the stress (from gravity) trying to pull the snow downhill exceeds the strength (from bonds between snow grains) of the snow cover. The avalanche danger increases with major snowstorms and periods of thaw. The most avalanche-prone months are, in order, February, March, and January. Avalanches caused by thaw occur most often in April.

About 90% of all avalanches start on slopes of 30-45 degrees; about 98% of all avalanches occur on slopes of 25-50 degrees. Avalanches release most often on slopes above timberline that face away from prevailing winds (leeward slopes collect snow blowing from the windward sides of ridges.) However, avalanches can occur on small slopes well below timberline, such as gullies, road cuts, and small openings in the trees. Very dense trees can anchor the snow to steep slopes and prevent avalanches from starting; however, avalanches can release and travel through a moderately dense forest.

Most avalanches occur in the backcountry, outside of developed ski areas. The Aspen Skiing Company does an excellent job of avalanche control inside the boundaries of the local ski areas. But if you are going to ski in the backcountry you can reliably avoid avalanches by recognizing and avoiding avalanche terrain. You cannot entirely eliminate risk, but you can minimize risk by using appropriate skiing technique, carrying and knowing how to use avalanche rescue gear; and turning back or altering your route if you detect signs of unstable snow.

For the most current avalanche forcasts and updates, link to the Colorado Avalanche Info Center.
The local Aspen Hotline Info number is 970-920-1664.