Boletín de aludes

Northwest Mountains

Crested Butte Avalanche Center
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Peligro de aludes

Fri
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 8 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Multiple triggered avalanches (Marble 1 and 2, Schuylkill Ridge, Pearl Mtn) earlier this week highlight the potential outcome if you encounter a slab above faceted weak layers near and above treeline.  Collapsing and cracking are clear signs you have found the problem.  You can dig into the snowpack to identify slab formation and look for surface clues to predict where slabs exist.  Lower-risk options exist below the treeline. 

Light snowfall on Thursday is not expected to increase the danger rating, but if you encounter 6 inches of new snow by day's end, the hazard is rising.

 

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    Soft slabs of recent and wind-drifted snow are sensitive to human triggers where they formed over thin crusts and faceted weak layers,  typically near and above treeline.  Buried weak layers are most widespread and well-developed on the north half of the compass above ~10,700', but have also been found above buried crusts on southerly aspects.  Underneath last week's storm snow, the old snowpack is highly variable due to droughts, record-warm temperatures, and previous extreme wind events. Expect variable feedback as you change aspect and elevation, or move from one part of a slope to another.  Slopes with the slab + facet ingredients can be remotely triggered or propagate wider than expected.  This video illustrates the problem.  

    (12/28/2025)

    The crown of a skier triggered persistent slab on Schuylkill Ridge.  The slab consisted of about 18" of recent snow over weak facets near the ground, and propagated about 350' wide.    

Avalanche Discussion

The primary avalanche concern remains tied to faceted snow that formed during the December drought and persists on select slopes. These weak layers are most commonly found on colder aspects above the Christmas rain line (~10,700 feet), particularly where terrain was sheltered from the extreme northwest wind event. Where recent snowfall and wind loading have created a cohesive slab over these facets, human-triggered avalanches remain possible in steep terrain. Given the variability in weak layer distribution and strength, an effective risk-management approach is to assess the presence or absence of a cohesive slab and carefully consider the consequences should it fail.

A storm system begins impacting the region Thursday morning. Current weather models suggest 1 to 4 inches of snow by sunset, though this moisture-rich system has the potential to overproduce. Should snowfall exceed expectations, avalanche danger may rise. The sensitivity of the current Persistent Slab problem will likely increase once storm totals approach or exceed six inches. Below treeline, where the danger is currently rated LOW, conditions could also worsen. A thin layer of faceted snow rests above the slick Christmas Crust at lower elevations and may produce a small soft slab problem on the north half of the compass if the storm exceeds the forecast by sunset.

As the storm intensifies Thursday night into Friday morning, avalanche danger is expected to increase, with the most hazardous conditions developing in the Northwest Mountains where snowfall totals will be greatest. Be prepared to dial back terrain choices on Friday, anticipate the potential for natural avalanche activity, and be sure to read the forecast before heading out tomorrow morning.

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