Bulletin d’avalanche

West Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Mon
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 8 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Steer clear of very steep, unsupported terrain holding wind-drifted slabs. Use cornices and scoured ridgelines to identify where wind has removed snow from some slopes and deposited it on others. Warmer temperatures and increased sun could initiate loose-snow avalanches on sunny slopes.

Problèmes avalancheux

  • Wind Slabs

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

    With another day to bond, triggering a wind slab will generally require steeper, more unsupported terrain. As slabs stiffen and become harder to trigger, they can also be more surprising if you do manage to find one. Fresher slabs may be found in high alpine terrain where winds were strong enough to continue transporting snow on Saturday.

    Identify likely wind slab locations by looking for clues like rippled snow or scoured surfaces in the surrounding terrain. Track changes in snow stiffness and depth over the underlying layer to pinpoint areas more likely to hold wind slabs.

    Test slopes and hand pits offer limited feedback once slabs become stiff and stubborn. The simplest way to manage risk is to avoid very steep, unsupported, wind-loaded features and complex or rocky terrain where wind slabs linger.

    (2/14/2023) 

    Example of a large wind slab avalanche in rocky, unsupported terrain.

     Photo: Jere Burrell - Guided Exposure

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    A bit more sun and plenty of soft snow out there equate to a chance of seeing small loose snow avalanches initiating in steep rocky, treed, or cliffy terrain. Keep track of what is going on above you on southerly aspects as the day warms. Rollerballs and very small loose snow avalanches are signs that you could see bigger ones.

    (3/13/2022)

    Stay off and away from steep, sunny slopes if you start seeing small loose snow avalanches.

    Photo: Alyssa Young

Avalanche Discussion

A few human-triggered avalanches were reported as of late Saturday afternoon in West North. A skier triggered a slab on a very steep (45+ degree), north-facing slope near the top of Table Mountain near the Mt. Baker Ski Area, and avalanche control work released another hard slab avalanche in a northerly-facing, wind-loaded pocket. Loose snow sluffing was the avalanche problem most people encountered today.

Observers in Snoqualmie Pass reported wind-affected snow surfaces but found minimal instability. Lack of access to Stevens Pass and along the Highway 2 corridor has hampered observations in that part of the Cascades.

Winds were calm on Saturday, and snow conditions were reported as excellent. The exception was in high alpine terrain, where strong winds were redistributing snow and likely forming fresh slabs. Be prepared to find more reactive or larger slabs if you head up high.

State and local resources are working diligently to reduce the impacts of destructive storms that occurred earlier this month. We can help by respecting affected communities, complying with road closures, and adhering to ski area uphill travel policies.

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