Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

The danger will rise to Considerable at higher elevations as warming temperatures cause wet avalanches and increase the threat of large natural or triggered slab avalanches on sunbaked slopes.  Several large persistent slabs ran yesterday (ex. Afley, Anthracites) and similar human-triggered or natural activity is expected today under our warming trend.  Slopes with a relatively shallow snowpack or rocky terrain are most problematic for skiers and riders on any aspect.  You can find safer riding and higher quality snow in wind-protected, shady terrain where the snowpack is consistently deeper than about 5 feet deep.  

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    January storms formed slabs averaging 1 to 3 feet thick over widespread persistent weak layers lower in the snowpack.  Persistent slab avalanches have the potential for wide propagation and remote triggering,  and may not give any warning signs. We've observed a recent uptick in natural persistent slabs on higher elevation southerly and westerly facing terrain over the past few days, where the problem appears to be most reactive right now.   The easiest and most reliable way to manage this problem is to ride on slopes consistently less than 30 degrees in steepness.  Other strategies for reducing your risk include riding on slopes where the problem has recently avalanched away, avoiding trigger points where the snowpack thins near rock outcrops or wind-eroded terrain features, or traveling where the snowpack is consistently deep (>150cm) and uniform. 

    A large persistent slab that ran 1/29 on the southwest side of Afley.  

  • Loose Wet

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

    As the snow surface gets wet later today, shallow wet avalanches will be easy to trigger and will release naturally from very steep, sunbaked slopes, especially near rock bands.  Look for natural avalanche activity, rollerballs, or pinwheels shedding from hot slopes to warn you of the developing problem.  Wet loose avalanches can cause trouble if they push you into a terrain trap or if they trigger a larger persistent slab.  There is isolated potential for large wet avalanches to occur today, either a long-running wet loose avalanche or a wet slab from a hot, rocky slope. Choose lower slope angles or colder aspects to avoid the issue.  

    Small wet loose activity like this was common yesterday, especially near and above treeline.  Expect more of the same with today's warmer temperatures.  

Avalanche Discussion

The combination of a northerly wind event on Saturday followed by rapid surface warming has caused an increase in natural persistent slab activity at higher elevations in the past few days, almost entirely on the southwest half of the compass.  With the near-record warmup peaking today, we've bumped the danger back to Considerable to account for this apparent increase in sensitivity of the persistent slab problem, along with numerous wet loose avalanches expected to run today.   The likelihood of triggering a persistent slab on higher elevation, seasonally windward aspects may fit more with "likely" by this afternoon.   A pattern of increasing natural persistent slab activity more than 10 days after the loading period ended is so unusual that I used one of my "phone-a-forecaster-friend" cards last night to get some outside-of-the-region perspective on our current danger equation.  Needless to say, uncertainty is high, but we have a stepping-back mindset given the poor snowpack structure, recent avalanche patterns, and climbing temperatures.  Fortunately, the most active slopes are self-policing human triggers right now with lower-quality snow conditions: relatively thinner snow coverage becoming hot and sticky each afternoon makes it an easy decision to go ride on northeasterly aspects where there is still high-quality powder and the snowpack is deeper.  Regardless of aspect, use extra caution in wind-affected terrain where slabs are more variable in thickness, or in shallower parts of the Southeast Mountains where the snowpack is thinner.  This forecaster observation from yesterday demonstrates how even on traditionally leeward aspects, you can find shallow areas where you are more likely to trigger a dangerously large avalanche on our well-advertised buried weak layers, similar to this remote trigger on Sunday near Taylor Pass.    

Events: Our next Fireside Chat is this Sunday, February 4 at 6 p.m. at High Alpine Brewing Company in Gunnison. A local snowmobiler will talk about his experience with an avalanche burial and rescue while snowmobiling last year.

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