An avalanche is a rapid flow of snow down a slope, from either natural triggers or human activity. In mountainous terrain avalanches are among the most serious objective hazards to life and property, with their destructive capability resulting from their potential to carry an enormous mass of snow rapidly over large distances.
All avalanches share common elements:
- a trigger which causes the sudden rupture of the snow pack,
- a starting zone from which the initial volume of snow is detached,
- a slide path along which the avalanche flows,
- a run out zone where the avalanche comes to rest;
- a debris deposit which is the accumulated mass of the snow avalanche once it has come to rest.
Sometimes, the deposit may be a mixture of snow, ice, soil, rocks and vegetation debris.