Bollettino valanghe

Northwest Mountains

Crested Butte Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

Weeks of dry weather and recent wind erosion have reduced the threat of avalanches on many slopes.  Expect stubborn wind slabs on recently drifted slopes, and give yourself a cautious margin for error on the shady side of the compass near and above treeline, where a low-probability, high-consequence persistent slab could still break deeper and wider. The safest and highest quality riding is in wind-protected terrain at lower elevations.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1.5–2.5

    Although instabilities are becoming increasingly harder to find, the most hazardous concern is the lingering threat of triggering a large slab that fails 2 to 4 feet deep on depth hoar, facets, and faceted crusts without obvious warning signs.  In the Northwest Mountains, these slabs are most likely to be triggered in terrain where slabs are thinner or variable in depth from past wind events. 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 ran naturally on the west side of Mt. Baldy on 1/10/2026.  

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1–1.5

    Strong to extreme northerly winds last week formed thin, hard slabs on features that collected drifting snow. The wind event mixed down to mid and low elevations, cross-drifting relatively small slabs onto weak, faceted snow surfaces - most commonly on the shady side of the compass where there was more snow available for transport and on higher southerly aspects.  These slabs will stand out as smooth, hard, lens-shaped snow formations, next to wind-eroded areas or softer, wind-rippled snow surfaces.  Although these slabs are typically stubborn to trigger now, skirt around these harder drifts in consequential terrain to avoid the threat of getting pushed into trees, rocks, or gullies. 

    An example of a wind-loaded feature that is best avoided in consequential terrain.   Look for the smooth, rounded, firm surfaces to identify the problem.  

Avalanche Discussion

We continue to assess the aftermath of last week's wind events, which brought strong to extreme northeast-to-northwest winds for several days, peaking on Saturday.  As is typically the case with extreme wind events, we observed extensive wind erosion in some areas, while wind loading appears to be rather limited: thin, hard wind slabs are scattered around various aspects and often collected at lower elevations where wind speeds were lower.  Keep your eyes open for the obvious smooth hard lenses of drifted snow that stand out amongst erosional textures.  Some of these will be thin wind crusts that aren't a concern, while others will be stubborn drifts that might knock you off your feet if you get one to pop.  This video of a skier getting caught in a wind slab in the San Juans over the weekend is a great example of what that looks like. 

Persistent slabs breaking in old December and November weak layers have become unlikely.  The combination of nearly two weeks of dry weather, along with more recent wind erosion events, has made the issue increasingly isolated and stubborn.  I'll borrow an analogy that the Utah Avalanche Center used yesterday: Imagine squeezing a spring between your fingers. As you apply force, the spring compresses and stores energy. Loading the snowpack with new snow or wind-drifted snow does the same thing—it compresses the system and increases stored stress. When you slowly ease your fingers apart, the spring relaxes and releases that energy gradually. Similarly, when there’s a prolonged break in loading, the snowpack begins to creep, adjust, and settle. As the system adjusts, the likelihood of a sudden failure—like a slab avalanche—decreases, though it doesn’t disappear entirely.

The thinner snowpack in the Southeast Mountains is more prone to losing slabs from both faceting and wind erosion, and our confidence is higher that the danger has finally subsided to Low there.  This video demonstrates the typical situation.  The Northwest Mountains may be there as well, or trailing close behind.  The larger slabs and very large natural that ran last week give us more uncertainty; we're looking for a bit more time and field data before we go there.  

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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