Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

Thu
Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 8 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

Most slopes offer safe travel without the threat of avalanches.  The only avalanche activity in the past week has been a few small hard slabs of drifted snow that formed during last week's wind event (Ex. Irwin, Marble).   Stay alert for isolated instabilities if you are traveling in high-consequence terrain: old slabs of drifted snow over weak facets could still surprise you.  Avalanche conditions are expected to start changing tomorrow and into the weekend with the arrival of new snow and winds.   

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1–1.5

    An extreme wind event last week formed a few thin, hard slabs scattered across all elevations, in concave catchments and behind abrupt transitions in the terrain. Where these drifts formed over facets on colder aspects, you might still be able to trigger one, and they're stiff enough to knock you off your feet.  Look for firm, rounded snow surfaces to identify potential features of concern. 

    Snowfall and wind drifting in early December formed slabs up to a couple of feet thick over facets near the ground.  These weak layers are most widespread on the northern half of the compass. Mild weather through the middle of December has helped the snowpack adjust to its current load, and in many areas, the slabs have decayed or been scoured away by winds. The last documented avalanche on these old, weak layers was accidentally triggered on 12/14.  Similar instabilities will be very rare, but not impossible.  

    An example of a thin, hard slab over sugary facets. The resulting avalanche would be small in size, but the hard snow surface could easily pull you off your feet or push you into a tree. 

Avalanche Discussion

We're emerging from an 18-day drought tomorrow.  Avalanche activity has been scarce in the last week, limited to a few small, hard slabs following last week’s extreme wind event.  Where these slabs formed over weak snow surfaces on colder aspects, they remain a small and stubborn concern in high-consequence terrain.  The thicker slabs that formed in early December have had two weeks of quiet weather to adjust or decay, and most slopes are expected to be unreactive. Recent reports of collapses and shooting cracks from Hunter Hill are a reminder that these older slabs still have the potential to surprise if you find the wrong slope.

A much-anticipated storm will bring changing conditions through the weekend.  We could see the danger level rise tomorrow, depending on how well the first pulse of moisture performs (See weather tab for details).  Given how weak our snow surfaces have become on colder aspects, it won't take much snowfall for shallow slab instabilities to form, especially because the new snow arrives relatively warm and dense.  With only modest accumulations expected tomorrow, instabilities should remain relatively small and easy to manage.   That will likely change by the weekend if we see the higher end of possible snowfall outcomes.  

Regions covered