Bollettino valanghe

Northwest Mountains

Crested Butte Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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In sintesi

Recently formed slabs up to several feet thick are expected to remain sensitive to triggers where they formed over fragile weak layers.   Large collapses yesterday and a natural cycle over the weekend tell the story.  Choose conservative slope angles or smaller terrain features to manage the hazard.  Avalanche problems are smaller and less common at lower elevations.  

Problemi valanghivi

  • Persistent Slabs

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

    Most avalanche concerns today involve soft slabs in recent and wind-drifted snow that formed over facets and faceted crusts. These slabs, up to several feet thick, are expected to remain sensitive to human triggers on some terrain features facing west, north, east, and southeast, and potentially on all aspects at high elevations.  The weekend snow fell on highly variable snow surfaces, so expect hit-or-miss feedback as you move through the terrain; collapses and shooting cracks are clear red flags. There is isolated potential for a slab failing in the upper snowpack to step down and trigger a deeper, harder avalanche near the ground. The most reliable way to manage this problem is conservative terrain selection—sticking to slopes under 30° or small terrain features without terrain traps.   Lower-elevation southerly aspects offer the safest snowpack, and slabs are typically smaller and less developed in wind-protected terrain.

    An example of an avalanche that broke about 2 feet deep on weak, faceted snow that was buried at the beginning of the weekend storm.  (1/26/2026) Photo: Crested Butte Avalanche Center

Avalanche Discussion

Yesterday's good visibility allowed us to better understand how our snowpack responded to the weekend storm.  As expected, the snow-favored Northwest Mountains saw a more widespread cycle, with many avalanches ranging from D1 to D2.5 in size.  The Southeast Mountains saw fewer avalanches, with sizes ranging from D1 to D2.  The largest avalanches in the snow-starved zone were right along the border of the two zones, and in long-running terrain such as Climax Chutes and Gothic.    Almost all of the avalanche activity broke in the new and drifted snow  - likely at the storm interface (our fragile January drought layer).   There were a few avalanches that appeared to pry out the thin, hard slabs that formed during mid January extreme wind event.  So far, we haven't documented any avalanches that broke deep into our early-season weak layers near the ground - let us know if you see one!  The pattern of fewer, smaller avalanches resulting from lower storm totals is why the Southeast Mountains are quicker to move to Moderate danger after the storm.  

Moving forward, we are re-categorizing the newly formed soft slabs into a new generation of persistent slabs.  Future instabilities in the recent snow should be limited to just the terrain where slabs formed over facets and faceted crusts.  Our pre-storm observations describe some of the characteristics of this January 23rd interface before it was buried (ex. Poverty Gulch, Baldy).  As the low-density snow from the weekend continues to settle into stiffer and more cohesive slabs in snow-favored areas, there may be increased potential for longer remote triggers or surprising slab behavior.  Of course, wind-loaded terrain has the thickest and most well-developed slabs.  The avalanche activity rose over the weekend helps demonstrate our most problematic terrain. We know that weak facets were well developed on west, north, and east aspects at all elevations, along with southeast aspects near and above treeline.  We have limited observations from high-elevation south- and southwest-facing slopes, and these slopes warrant similar caution given the wind loading patterns and a few notable avalanches on these aspects.   

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