Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Avalanche conditions have quieted down greatly since last week's major storm.  The snowpack continues to trend toward equilibrium during this prolonged dry period; however, weak layers near the bottom of the snowpack have not changed significantly.  The most suspect terrain is found at upper elevations facing the compass's north half (particularly north and east aspects), which don't show signs of recent avalanche activity.  You can find lower-risk conditions at low elevations, southerly aspects, or low-angled terrain.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Last week's storm produced a widespread avalanche cycle on November 26-27. Those slabs have now settled to 1 to 3 feet thick over faceted snow that formed earlier this winter. The snowpack is gradually adjusting now: stability tests are improving, and signs of instability have diminished as the problem has become more difficult to trigger. The most problematic slopes face west, north, and east, along with higher-elevation southeast-facing slopes.  Slopes that naturally avalanched last week offer lower-risk options for steep terrain on those aspects.  Move to smaller, less consequential terrain features or low-angle terrain when in doubt.  

    A pair of large avalanches in upper Cement Creek on a northeasterly-facing slope at 12,200ft. These avalanches are estimated to have released last weekend during a period of elevated winds. 

Avalanche Discussion

In the Northwest Mountains, the persistent slab problem has become unlikely to trigger, and the features of concern are isolated across the landscape.  Many steep slopes, highlighted by the Persistent Slab distribution rose, avalanched naturally during last week's widespread cycle; most of these slopes now lack a slab.  Observations and stability tests on intact snowpacks (no previous avalanche activity) show notable improvements in basal weak layer hardness with clear signs of rounding (1,2).  Lingering concern for a triggered avalanche is a product of variability in alpine terrain due to previous winds.  There could be outlier slopes that are just shallow enough to prevent weak layers from gaining strength.  Even though avalanche conditions have greatly improved in the 10 days since the major Thanksgiving storm, evaluate slopes where you expect to encounter Persistent Slab structure before you enter steep and consequential terrain.

In the Southeast Mountains, the Persistent slab problem has become harder to trigger but more problematic than in the Northwest Mountains. The natural avalanche cycle during the Thanksgiving storm was less impressive and released fewer slopes. Due to less snow during the Thanksgiving Storm, slabs are generally thinner, and the snowpack shallower, which we suspect makes basal weak layers slower to heal.  These two factors make a triggered slab avalanche more likely in the Southeast Mountains.

As the upper snowpack continues to facet and lose strength, stay alert for small loose dry avalanches on sustained, steep terrain.  The snow on top of old bed surfaces is losing strength rather quickly, as shown in this video from Mt. Axtell earlier this week. 

Events: Avalanche Awareness Night is at the Center for the Arts this Saturday. Doors open at 6, show starts at 7. We will have presentations for the first half and live music for the second half of the night. The Beacon Brush Up is then behind the Crested Butte Community School on Sunday from 9 a.m.- 2 p.m.  Details are here. 

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