Boletín de aludes

East Slopes Central

Northwest Avalanche Center
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Peligro de aludes

Wed
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

You may still be able to trigger small avalanches in lingering pockets of wind drifted snow. The base of cliffs, ridgelines with little vegetation, and alpine bowls at high elevations are the most likely areas to find these unstable slabs. If the snow feels stiff or sounds hollow, consider lower angle routes or terrain sheltered from the wind. Early season hazards buried just below the surface, like rocks and stumps, can increase the consequences of being caught in even a small avalanche. 

Problemas de aludes

  • Wind Slabs

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

    Winds have calmed, temperatures have dropped, and precipitation has tapered off. While this leads to an overall decrease in avalanche danger, you could still trigger lingering small wind slabs at upper elevations near ridgelines. We have limited observations from alpine terrain due to challenging access at lower elevations. However, we expect these slabs may have formed on slick crusts or older weak snow from mid-November, and we have uncertainty about how easily they can be triggered. This uncertainty makes it important to assess new terrain before committing to steep slopes and observe changing conditions as you gain elevation.

    Visual clues such as cornices or wind drifts can help you identify wind loaded terrain. Some older wind slabs and wind textured surfaces may now have a dusting of new snow on top, making them more challenging to recognize. So you can also use quick hand pits or your probe/ski pole to feel for stiffer layers of snow over softer layers. Snow that feels stiff, hollow, or cracks shooting away from your feet or equipment are signs you should use low angle routes or move to terrain sheltered from the wind. Be especially cautious in extreme terrain where even a small avalanche could push you into rocks, stumps, or over cliffs.

     

     

    (12/16/2021)

    Small cornices and drift formations indicate the primary wind direction (right to left in this photo and point towards potentially wind loaded slopes.

    Photo: Katie Warren

Avalanche Discussion

Expect frigid temperatures for Tuesday, with highs in the single digits. Bring and wear extra layers and monitor exposed skin for cold injuries. Consider using a buff or face mask to protect your nose and mouth from wind chill. 

After a relatively benign weather day on Tuesday, a powerful winter storm is likely to impact the Cascades on Tuesday night, with a chance of significant accumulations on the east slopes of the Cascades. Expect conditions on Wednesday to be drastically different, with heavy snow, wind, and rapidly increasing avalanche danger. This storm will be the first significant test of the weak, sugary layer of snow formed from the prolonged, cold, dry weather in mid-November. We still have a lot of uncertainty about the extent and distribution of this weak snow layer. But observations from Mission Ridge Ski Patrol indicate it is still prevalent in and around the ski area. So if you are traveling in the mountains on Tuesday, take note of the current snow surfaces, as they may be Wednesday's weak layer. 

Access at lower elevations is challenging, and we have limited information about the snowpack at upper elevations. If you are headed out into the mountains, be prepared for long approaches on thin snow cover. Many motorized trailheads have limited snowpack, and most have yet to begin grooming operations. In addition, the recent snow may have shallowly buried rocks, stumps, creeks, or other hazards.

If you are out and about in the mountains, let us know what you find by submitting an observation.

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