RockTalk: Avalanche Formation and Release

This edition of RockTalk covers the science of how avalanches form and what the Colorado Avalanche Information Center (CAIC) is doing to reduce the danger of avalanches. Digital PDF download. RT-03-04D

Excerpt:

Slab Avalanche Release

Avalanches release when the unstable snow cover-comprised of a slab layer on top of a weak layer-is stressed to the point that it can no longer hold itself in place and it fails. This may happen almost instantaneously, or it may happen in a progressive failure of one small area at a time, with minutes to hours passing before release. A tug-of-war analogy is useful in understanding how this might happen.