GEOG 1350 Chapter : Snow Avalanche-2.docx
20 Oct 2014
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Document Summary
Types of avalanches: point release avalanche, begin as an initial failure after a snowfall, sliding causes more failures in the adjacent snow pack, causing the trough to widen, slab avalanches, occur when a snowpack fractures along a weak layer parallel to the surface, these move as cohesive blocks leaving behind a scarp, these are the more dangerous of the two avalanche types. Such a layer can form from wind or from hoar: wind, blowing snow can accumulate on the lee slope of mountains (downward wind slope, wind can deposit a layer of light snow crystals on a layer of more compacted snow, the boundary between the two layers could become a horizon along which failure could occur, hoar layers of hoar have less strength than the rest of the snowpack, can form deep in the pack in air pockets or on the surface, hoar changes little over time.
