Boletín de aludes

Olympics

Northwest Avalanche Center
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Peligro de aludes

Mon
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 6 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

The recent 10-12" of snow combined with winds to form large slabs that you can trigger, particularly at upper elevations. Steer around wind-affected snow, approaching upper-elevation terrain with caution.  Fresh cornices are large and sensitive and may break off unexpectedly, so navigate ridgelines with caution and reduce your exposure to cornices overhead.

Problemas de aludes

  • Wind Slabs

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

    Friday night and Saturday's storm brought around 10" of snow, with 14" of snow now sitting on the 12/21 crust. Sustained moderate winds at ridgeline during the storm blew that snow around to create large slabs and cornices on N aspects that will be sensitive to human trigger near and above treeline. Look for visual clues to identify wind-loaded slopes, such as the direction of fresh cornices or wind-lips, and avoid nearby slopes steeper than 35 degrees. Professionals noted some reactivity above and below the 12/21 crust, which will provide a bed surface for any large avalanches. In areas where there is a firm slab, it could propagate widely and fracture above well above you on the slope. Whumphing or cracking of the snow is a quick indicator that you are heading into wind-affected and unstable snow.

    We don't know how dangerous wind slabs will be at upper elevations, so if you travel above treeline, prepare to make your own assessment and avoid all slopes steeper than 35 degrees if you find widespread areas of firm or punchy snow.

     

    (12/23/2020) Example: Blowing snow from moderate southeasterly winds was forming thin new wind slabs. Chair Peak, 5200' N aspect.

Avalanche Discussion

Professionals found 14" of snow that was generally right-side-up and bonding. The crust limits our avalanche concerns to the snow that fell since 12/21. 

Cornices are a relatively novel concern for the Olympics this season. Practice save travel and avoid traveling under corniced slopes, which are the same ones you should avoid due to their wind loading.

You could still trigger Dry Loose avalanches that run rapidly on the crust in less wind-affected areas and below the treeline.  If the sun comes out, which is uncertain on Sunday, watch for signs of rollerball activity and adjust your aspect to avoid triggering a Wet Loose avalanche.

Thin snow coverage still exists along ridgelines and at lower elevations. Give yourself extra time to deal with these travel challenges. 

2020-21 Forecast Schedule: Avalanche danger ratings will be issued for the Olympics every Friday through Sunday and during mid-week holidays. During the week when the Hurricane Ridge road is closed, forecast information will be updated daily to include expected conditions and relevant travel advice under the No Rating label.   

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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