Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 7 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

There are two types of slab avalanches you can encounter today. Both primarily exist on the northern half of the compass. The more likely problem to encounter is small, hard slabs that formed at all elevations on the lee sides of terrain features. These old wind slabs are responsible for multiple skier-triggered avalanches over the last several days. The more significant, but less likely to trigger avalanche problem would be a slab avalanche releasing 1.5 to 3 feet deep on old, persistent weak layers. You can reduce your exposure to these avalanche problems by riding in wind-sheltered terrain, where you will also find the best snow quality for skiing and riding. 

Avalanche problems

  • Persistent Slabs

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

    The most concerning avalanche potential continues for the possibility of human-triggered slabs that fail 1.5 to 3 feet deep on depth hoar, facets, and faceted crusts. In some cases, these slabs could also be triggered from low-angle slopes connected to steeper slopes above. Obvious signs of instability, like collapsing or shooting cracks, have disappeared, so you can't count on those obvious warning signs. In the Southeast Mountains, slabs are most likely to be triggered in terrain where slabs are more cohesive from previous windloading. The most reliable way to manage this problem is by choosing slope angles less than 30 degrees.  Southerly aspects and elevations below ~10,500' offer safer snowpacks, where slabs are less common and weak layers are often capped by stronger crusts. 

    A large persistent slab on a wind-loaded slope near Crystal Peak that likely ran around January 10th during a previous wind event. 

  • Wind Slabs

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

    A new round of thin, hard slabs were created by an extreme wind event late last week. These slabs have typically formed where the old snow surface was soft and faceted. As those winds flowed through the mountains and valleys, they cross-loaded terrain features. This cross-loading even occurred at lower valley elevations. The wind direction aloft has been out of the north, so the distribution of this avalanche problem doesn't fit with a typical wind slab avalanche problem. These slabs will stand out as smooth and hard lens-shaped snow formations, next to wind-eroded areas or softer, wind-rippled snow surfaces. 

    In this avalanche example, you can see where the slab formed on the lee or cross-loaded side of the subtle ridge line. To the lookers' right and left of the slab, you can see wind erosion with some raised tracks.

Avalanche Discussion

The most notable change in backcountry conditions has been the continuation of northerly winds, which peaked with extreme wind speeds on Friday night into Saturday. Those winds have changed the snowpack across the forecast area, with widespread wind erosion and the formation of thin, hard slabs. The Gunnison River Basin is at 58% of the 30-year median peak, and we haven't seen a notable winter storm in over a week. So there wasn't much snow available for transport, but those winds were strong enough to erode wind-exposed terrain and transport what little soft snow was available. One positive way to look at this wind event is that snow surfaces are often uninviting in the more susceptible areas for triggering a slab avalanche. Backcountry riders will now often be pushed to wind-sheltered areas where it will be less likely to trigger a slab avalanche. 

The below treeline avalanche danger rating dropped to LOW, as confidence increased last week that the persistent slab avalanche problem was either stubborn and isolated or non-existent at those lower elevations. The recent wind event and formation of thin, hard slabs threw a little wrench in the danger trend. Those hard slabs are small, and it will be unlikely for them to cause much harm by themselves, unless they were to push you into a more hazardous terrain feature. The potential size and consequences of the problem can fit at the lower end of the danger scale, but you will still likely find yourself avoiding those hard slabs while searching for better snow quality. 

Upcoming Outreach Events:  

Fireside Chat:  Jan 23 Dave Scheefer "Historical avalanches in Gunnison County."  Mallardi Theatre 5-7 pm.

Trailhead Day: Jan 24, Slate River, 10 am-2 pm

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