Bollettino valanghe

Mt Hood

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You could trigger a slab avalanche at higher elevations where you find recent accumulations of heavy snow above lower density snow. At lower elevations, rain and mixed precipitation make loose wet avalanches possible where you find wet snow surfaces. Stay safe by choosing slopes under 35 degrees and steer around convex rolls and unsupported slopes such as those above cliffs or creeks.

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    You can trigger a slab avalanche where you find recent accumulations of heavier snow above lighter snow. Slabs will be most likely to be found above ~6000' Wednesday but may begin to form at lower elevations as new snow arrives. Cracking, collapsing, and whumphing sounds are clues that slab avalanches may exist. Identify and navigate around slopes with more than about 6" of new snow that are over 35 degrees.  Steer around convex rolls and unsupported slopes such as above creeks and cliffs.

    (11/25/2020) Test slopes can give you a lot of good information about how new snow has set-up after or during a storm. This test slope shows that storm slabs are sensitive and propagating easily.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1

    Rain and mixed precip wetted the surface of the snow up to around 6500' Tuesday. An unstable set up of wet, heavy snow sitting above a layer of lighter snow exists.  This is a recipe for wet loose avalanches on all aspects. Pay attention to rising temperatures. Increasing roller balls and pinwheels are an indication the snow surface is weakening. Stick to terrain below 35 degrees if you experience rain or see rollerballs beginning to accumulate snow as they roll. With a firm crust below the surface, even a small wet avalanche may easily entrain more snow and have the power to knock you down. Use extra caution around terrain traps like cliffs and gullies.

     

    (12/13/2020) Roller balls are an early sign of wet snow. If these roller balls had grown any larger we would have chosen lower angle terrain to avoid triggering a loose wet avalanche.

Avalanche Discussion

Rain and mixed precipitation made it's way up to around 6500' on Tuesday before turning back to light snow in the late afternoon. Observations were very limited, but no avalanche activity was reported Tuesday. At lower elevations expect heavy wet surface snow. Loose wet avalanches will be possible in terrain above 35 degrees, but challenging travel may be an equal hazard. At higher elevations, where snow has accumulated, slab avalanches will be possible. Recent snow will be much denser than the snow below and this "upside-down" structure is a good set up for slabs. Slabs may be possible on all aspects, but will be larger at higher elevations and on wind drifted, lee slopes.

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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