Boletín de aludes

Stevens Pass

Northwest Avalanche Center
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Peligro de aludes

Sun
Alta montaña
2 · Moderado
Límite del bosque
1 · Débil
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Expect increasing winds to create shallow but reactive wind slabs in alpine terrain on Saturday. The cool temperatures have likely preserved some weak layers at upper elevations, so it may not take much to begin seeing small wind slabs again. Keep an eye out for yawning glide cracks, and stay out from underneath them. 

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    Westerly winds will pick up as the day progresses, and begin drifting snow in the somewhat limited higher-elevation terrain within the Stevens Pass zone. The snow has been sitting around for a while now, and surfaces are a mixed bag of crusts and facets. Not all surfaces are conducive to drifting into slabs, but there is still a fair amount of soft, 'recycled powder' for the wind to blow around. Look for snow grains to bounce over ridgelines, and you might even see plumes on the higher peaks later in the day.

    Feel for stiffer snow and look for cracking within any fresh drifts that you find. Steer around steep slopes that are freshly loading, or if you find signs of instability.

    (12/14/2022)

    Example photo showing blowing snow from alpine ridgelines.

    Photo: Willie Webster

Avalanche Discussion

Avalanche danger was generally low for a few days, but this bump in westerly winds ahead of the next storm may once again introduce isolated problems to higher terrain. Some interesting observations this past week showed a large glide crack opening on a southeast-facing slope of Jove Peak. Stay off of and well out from under slopes with glide cracks, especially if the sun warms steep sunny slopes. Glide avalanches are difficult to predict and they can release with little warning. There are isolated rock slabs capable of producing these avalanches in the Stevens Pass zone.

A couple ofweak interfaces were buried last week, including patchy surface hoar, and have been slow to heal. These layers generally haven't been tied to instability, but there also has not been much of a slab on top, yet. You can find the layers in snowpack tests about a foot below the surface. Observers have been reporting a mixed bag of surface conditions, ranging from soft 'recycled pow' with facets and surface hoar on sheltered, northerly aspects to various degrees of crusts on southeast to southwest slopes. 

Layers of weak snow and crusts were buried by a series of storms in mid to late November. This layer is now near the ground and has been observed to be gaining strength and rounding. These older layers generally haven't been a problem for avalanches in this zone as much as in the East Central zone, though it's something to consider, especially where the snowpack is less than 4 feet deep, and following any major storm event.

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