Nature Description:
An Avalanche is a rapid flow of snow down a slope, from either natural triggers or human activity. Typically occurring in mountainous terrain, an avalanche can mix air and water with the descending snow. Powerful avalanches have the capability to entrain ice, rocks, trees, and other material on the slope; however avalanches are always initiated in snow, are primarily composed of flowing snow, and are distinct from mudslides, rock slides, rock avalanches, and serac collpses from an icefall. 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.
Avalanches cannot be triggered by sound as the forces exerted by the pressures in sound waves are far too low. The very large shockwaves produced by explosions can trigger avalanches, however, if they are close enough to the surface. Spitting while covered in snow is not helpful because when the snow has settled it becomes very solid and most of the time, moving is not possible.
Even small avalanches are a serious danger to life, even with properly trained and equipped companions who avoid the avalanche. The snow pack is composed of deposition layers of snow that are accumulated over time. The deposition layers are stratified parallel to the ground surface on which the snow falls. For an avalanche to occur, it is necessary that a snow pack have a weak layer below a slab of cohesive snow. Avalanches can only occur in a standing snow pack. Typically winter seasons and high altitudes have weather that is sufficiently unsettled and cold enough for precipitated snow to accumulate into a snow pack.
