Not even experts are able to accurately predict them. There are, however, a number of factors that greatly increase avalanche danger. Every person who ventures out during the winter should be aware that leeward slopes accumulate a great deal of wind-deposited snow and may become very unstable. In addition, avalanches are most common on slopes of between 30 and 45 degrees. Storms nearly always increase avalanche danger considerably.
Most avalanches occur during or just after storms.
It is a rare Jackson Hole winter that passes without at least one skier or snowmobiler being buried in a snow slide. All too often, the victim does not survive. If you want to go out in winter you should learn to evaluate avalanche danger. This article is far too brief to permit a full description of avalanche safety, so if you plan on spending time out in the snow, take the time to learn more before you go.