EARTHSC 2GG3 Lecture Notes - Lecture 7: Avalanche, Blowing Snow, Ice Crystals
17 Dec 2019
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Document Summary
S n ow c l i m a t o l o g y. The length of the snow season depends mainly on latitude and altitude. The amount of snow on the ground depends on slope of the and elevation, amount of snowfall, and winds: snow accumulates on slopes less than about 45o. Slab avalanches: snowpack fractures along a weak layer at depth, moves as a cohesive block, more dangerous than point-release avalanches. Ice crystals change slowly once buried: overlying and underlying snow layers gain strength, leaving the buried surface hoar as a weak layer. Some happen when normal daytime heating or an inflow of warm air raises the temperature of the snowpack: most avalanches occur naturally during or soon after snowstorms. In most recreational accidents, a person triggers the avalanche. Some avalanches are triggered intentionally as part of avalanche-control programs. Track: path of acceleration and maximum velocity, run-out zone, deceleration and deposition.
