VIDEO: Why Cold Temperatures Cause Avalanches

AvyBrains | | AvalancheAvalanche

Cold temperatures cause facets (incredibly angular, low density snow grains) to form. 

Why do we care about facets?  Becuase facets cause snow pack instability and avalanches.

1ºC per 10cms of snow is the threshold for temperature gradient needed to grow facets. 

Cold temperatures and facets are characteristic of the intercontinental and continental snow packs of Utah, Colorado, Wyoming, Montana, New Mexico, Idaho, and the Canadian Rockies.  If you ski or ride these regions, you need to know about facets.

Facets.
Facets.

Anywhere with cold temps can grow facets.  California’s snow pack currently has facets due to recent cold temperatures.

Basal facets on Castle Peak, CA yesterday. photo: Sierra Avalnche Center
Basal facets on Castle Peak, CA yesterday. photo: Sierra Avalnche Center
stock avalanche image.
stock avalanche image.

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3 thoughts on “VIDEO: Why Cold Temperatures Cause Avalanches

  1. Excellent explanation on how facets grow in the snow pack.

    This is the kind of thing I like to see on Snow Brains.

    Thanks,

    Miles

    1. You’re welcome, Tom. We’re trying to get as much avy info as we can up here. Thanks for the kind words.

  2. A pit dug at nearly identical elevation and aspect (albeit lower angle, 13° +/-2°) in Tahoe Meadows yielded similar results with Q2 failures along the upper basal facet layer (0-15 cm layer). The observed temperature gradient (2° C/10 cm !!!) was larger than that reported for Castle Peak. Crystal grain sizes and overall stratigraphy throughout the snowpack was consistent with SAC’s results. Stiff snowpack overall, should be good to go once the sticky icky shows up, simmers down, and puts everything on lock. Classic early season slightly above average precip below normal temps snowpack. peace

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