[Page 27]An avalanche is a slide of snow down a slope. It originates in what is called a starting zone, typically high up on a slope, beneath cornices, or in a bowl on a mountainside. The avalanche continues along the avalanche track of snow movement. The avalanche track commonly follows a slope or chute that is treeless and has debris deposited by the avalanche at the bottom of the slope. The track may be just a few feet long, or several hundreds of feet long. The avalanche ends where the snow stops in a runout zone, the site of the largest piles of snow and debris such as trees and rocks.

Snow avalanches may occur as a loose snow slide or as a slab avalanche depending ...