Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired last year. You’re viewing past conditions, not the current bulletin.

Highlights

The snowpack has quieted since last week's storm, but the potential to trigger a large and dangerous avalanche lingers on a few steep slopes.  The most suspect features are where the snowpack is atypically shallow with variable depths from rock bands or wind effects.   Southerly aspects offer safer riding - stay alert for isolated wet loose instabilities if surface crusts thaw before cloud cover arrives.  The avalanche danger will rise tomorrow due to heavy snowfall and strong winds.  

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–2.5

    There is isolated potential to trigger a large, hard slab avalanche on the well-developed facets or depth hoar layers in the middle or bottom of the snowpack.  These avalanches are most likely to be triggered on the northern half of the compass and where the snowpack is unusually thin and weak. Be cautious of very steep, rocky, or wind-affected terrain with variable snow depths.   Choose slopes with a deep and uniform snowpack to reduce your risk.  Southerly slopes typically lack the problem due to previous meltwater strengthening the snowpack.  

    Last week's snow now shows evidence of bonding to what is generally a small-grained, poorly developed interface. Stay alert for isolated exceptions on colder aspects. Surface hoar or very shallow bed surfaces could still be problematic. 

    This persistent slab avalanche caught and carried a snowmobiler last weekend on East Beckwith. The avalanche broke on the January drought layer 2 to 3 feet deep in the middle of the snowpack.  Note how the terrain has variable depths and shallow areas due to wind effects.  (3/8/2025) Photo: Care Flight

Avalanche Discussion

Yesterday's forecast discussed the three prominent weak layers in our snowpack: the large and well-developed facets and depth hoar from our December and January droughts and the March 3rd layer (generally small-grained facets) buried by the most recent storm. Evidence around the region (Schuylkill Ridge, Star Pass, Treasure Mtn, Grand Mesa) continues to suggest that the small-grained layer in the upper snowpack is bonding and becoming unreactive (or perhaps dormant until tomorrow's loading).  Today's travel advice is shifting back to focus on deeper weak layers, which are now the most likely failure plane in the snowpack.  Yesterday's shooting cracks on Hunter Hill (see video) are a great example of how this issue is most problematic where the snowpack is shallower and weaker.    It's no guarantee, but riding where the snowpack is consistently deeper than 2 meters will significantly reduce your chance of triggering an avalanche.  From a zone-wide perspective, there are fewer weak, shallow slopes in the Northwest Mountains, especially in wind-sheltered terrain. Thus, there is a lower likelihood of persistent slabs in the Northwest Mountains and a lower danger rating below treeline.   

Expect changing conditions and increasing danger tomorrow with new snow and strong winds on the way.  Our current snow surfaces are a variable mix of melt-freeze crusts, wind compacted snow, and near-surface facets.  Like last week's storm, you can expect storm instabilities to be more sensitive or persistent longer where they form over facets.  These observations from Schuylkill Ridge and Upper Cement show that near-surface facets are more prevalent on the north half of the compass, with some larger radiation recrystallization facets above crusts forming on the shoulder aspects (east or west).    

Regions covered