Bulletin d’avalanche

East Slopes South

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

Blowing snow should be obvious on Friday - so pay attention to where it's drifting to help you identify problematic slopes. You’ll find this wind-blown snow on the leeward side of ridges, below cornices, and under rock and cliff bands. Default to lower angle, less exposed slopes if you see shooting cracks or hear audible whumphs. 

Problèmes avalancheux

  • Wind Slabs

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

    Wind slabs will continue to grow in depth and distribution as strong west winds continue to drift new snow into cohesive slabs. Some of these slabs could be quite reactive and break in surprising ways if they rest on weak snow over a crust. 

    Blowing snow should be obvious Friday, so pay attention to where it drifts to help you identify what slopes are loading up. You’ll typically find these wind drifted slabs lurking on the leeward side of ridges, below conices, and under rock and cliff bands. Look for snow surfaces that appear ‘fat’ or textured to help you spot where the wind has been at work. Move to less exposed slopes if you notice shooting cracks or hear audible whumphs. 

    (12/31/2023)

    Consider avoiding pockets of drifted snow if you notice signs of instability like this. 

    Photo: Joe Dellaporta

Avalanche Discussion

The winter storm train officially commences across the Pacific Northwest this weekend. You may be hungry to find the goods in the coming days, but remember, the danger is only rising now. Recent snow accumulations (and more on the way) buried weak old surfaces, consisting of surface hoar and facets over a thin crust (1/2 SH). On Wednesday, this new interface showed signs of reactivity in snowpack tests in East Central. While not much of a slab exists over this layer yet, as the week progresses, we will be in a "trickle-in" weather pattern with light snow and increasing winds. Additional snow will progressively build more of a slab on top of these suspect weak layers, so expect a slow and steady increase in the avalanche danger. As we approach the weekend, a more robust storm system may be quicker to overload these layers.

NWAC forecasters were out in Ahtanum Meadows on Tuesday. The roads were snow-covered and groomed from the snowpark, but continuous coverage off-trail did not begin until around Colver Flats (6200ft). Up near Darland Mountain, snow depths were between 2-3ft. Unfortunately, southern aspects are the exception, and they have melted back significantly with lots of ground showing. 

Early season conditions still exist across much of the zone. Look for hidden hazards such as downed trees, stumps, creeks, and rocks. 

Régions couvertes