Boletín de aludes

Presidential Range

Mount Washington Avalanche Center
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Peligro de aludes

Thu
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 7 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Avalanche conditions remain dangerous. Large, destructive avalanches could occur naturally or be triggered by you on steep east-facing terrain above 3000 ft in wind-drifted snow. It is also possible that avalanches could break deeper in the snowpack on weak snow. Carefully planned travel and snowpack assessments are critical for safer travel in avalanche terrain today. 

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2.5

    What and where is it: New wind slabs could be multiple feet thick and found in north, east, and south-facing terrain above 3000 feet. These slabs were observed to have a strong-over-weak structure yesterday, and with the increase in wind speeds last night and into today, it likely has increased the size and reactivity of these slabs.

    How can you recognize it:  Active blowing snow and, if you have visibility, plumes of snow blowing at the ridgelines are signs that wind slabs are still forming and likely to be reactive. If you choose to enter avalanche terrain and find deep drifts of snow that go past the tops of your boots, shooting cracks in the snowpack, or recent avalanches, you have found a dangerous and large wind slab.

     How can you manage it: Minimize time spent underneath large, open east-facing snow slopes and make conservative terrain choices if you choose to travel in or around avalanche terrain. Consider that natural avalanches are possible today and could step down into a harder, older, more destructive persistent slab on top of a slick melt-freeze crust and run far into runout zones.

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    2–3

    What and where is it:  Old, hard slabs are sitting on top of weak snow on top of a slick melt-freeze crust formed on January 10th. These slabs are likely buried and hidden under new wind slabs between 3000 and 5000 feet in elevation on easterly aspects. 

    How can you recognize it: This avalanche problem won’t be identifiable from the snow surface. Probe to identify if the structure of a weak layer and a crust is present; you should be able to feel these hardness changes. If you find this structure, consider digging deeper into the snowpack and use tests like an extended column test (ECT) and propagation saw test (PST) to assess the propensity for propagation. 

    How can you manage it:  Understanding where this problem exists is the best way to manage this problem. Minimize your time spent underneath large, open east-facing snow-covered slopes. Recognize that large new wind slabs should be top-of-mind today and that this buried old slab could increase the destructive potential of a large wind slab avalanche today.

Avalanche Discussion

We have been in a period of prolonged elevated avalanche hazard, and I know that can be fatiguing, as there is the desire to get out and recreate. Keep in mind that the snowpack may be subtly changing, with weak layers becoming weaker as snow metamorphosis and faceting continue, while the additional snow and wind add stress. Because of this, each day warrants a fresh assessment, and consider that it may be time to employ patience to give these weak layers time to adjust to these new loads. 

With any persistent problem, there is uncertainty, uncertainty of where it exists and just how much stress it can handle. There are unlikely to be many, if any, warning signs, but the avalanche these layers could produce would be very large, destructive, and could run far into runout zones like the floor of Tuckerman Ravine and the ends of paths in Gulf of Slides. 

Your best tool for assessment will be evaluating the consequences of a slide. Risk tolerance is personal, but the possibility of an avalanche stepping down should be factored into your travel plans if you travel on a slope that has both buried weak layers and large surface wind slabs. Consider keeping terrain simple with wide margins.

OBSERVATIONS: Please consider submitting an observation on our website or in the new Avy phone app of what you are seeing in your travels. Submitting an observation hones your skills, informs other users, and improves our forecasts. 

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