Bulletin d’avalanche

West Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Mon
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 2 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Avalanche danger will decrease as the storm tapers, but areas of wind-drifted snow require investigation before committing to bigger terrain. When in doubt steer towards more planar, supported, and lower-angle terrain. Pay attention to sunny slopes if the clouds thin out in the afternoon.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    The risk of triggering an avalanche is higher on slopes where the wind built deeper, more sensitive slabs. When the wind is blowing, drifting snow will show you which slopes are loading up. When it’s calmer, use cornices, scoured snow surfaces, and other clues to figure out where stiff wind slabs could be hiding.

    Pay attention to signs of instability like whumping, shooting cracks, or recent natural or human-triggered avalanches. Track the depth of new and wind-drifted snow as you gain elevation and change aspects by measuring how much snow sits over the rain crust. Use small cornices, test slopes, and other simple tests to evaluate the bond of new and wind-drifted snow layers. 

    (12/31/2021)

    Keep an eye out for wind-affected snow and signs of wind loading. These wind-textured surfaces on the ridge indicate the slope to the left is wind-loaded.

    Photo: Dallas Glass

Avalanche Discussion

Conditions in neighboring zones were mixed on Saturday. Snoqualmie Pass saw just enough new snow and wind to create small and shallow wind slabs. Minimal wind and snowfall was recorded at Stevens Pass. In West North, Mount Baker Ski Area reported numerous large avalanches with control work on Saturday morning and also a handful of human-triggered avalanches in nearby backcountry terrain. Some backcountry observers found thick wind slabs of moist new snow became unreactive and cracking and other signs of instability tapered off.  But another team triggered an avalanche from low on a slope with one person caught and partially buried.  No natural avalanches were observed but visibility was too poor to say for sure.

Be ready to assess stability and find conditions different than expected on Sunday. The diverse range of weather effects from this storm means the actual avalanche danger and the kind of avalanches you might find vary widely between different parts of the same forecast zone.

Régions couvertes