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What is an Avalanche?

How Do Avalanches Start?

Avalanches require some type of force to trigger the mechanisms that lead to snowpack failure.

Natural avalanches are triggered by natural forces, such as loading from new snow, windblown snow, and rain. Other common natural triggers are a rapid increase in temperature or sudden, strong solar radiation. The vast majority of avalanches are triggered naturally.

Natural avalanche activity is a sign that human-triggered avalanches are more likely.
Natural avalanche activity is a sign that human-triggered avalanches are more likely.
Monashee Powder Snowcats

Human-triggered avalanches occur with the weight of a person or a machine causing the failure. If the snowpack is especially precarious, avalanches can be triggered from many metres away.

This avalanche was triggered by a skier at the top of a convex roll, where the slope rapidly steepened. Fortunately, no one was caught.
This avalanche was triggered by a skier at the top of a convex roll, where the slope rapidly steepened. Fortunately, no one was caught.
Jordy Shepherd

Artificial triggers such as explosives are used by professionals to deliberately release avalanches. This approach is used in places such as inside ski area boundaries and on highway passes, and is designed to keep avalanche sizes relatively small, before they build up to become more destructive.

Explosives are used to trigger avalanches when no public is in an area in order to avoid large avalanches when the public is at risk
Explosives are used to trigger avalanches when no public is in an area in order to avoid large avalanches when the public is at risk
Marmot Basin