Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
4 · Forte
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In sintesi

7:15a Update. Avalanche Warning for high precipitation rates and warming temperatures. Rain and heavy snowfall will create very dangerous avalanche conditions and difficult travel . Expect large natural avalanches in many areas. Saturday will be a good day to avoid traveling in the mountains. 

Problemi valanghivi

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1.5–2.5

    The best way to stay safe is to stay well away from and out from under slopes steeper than 30 degrees. Better yet, avoid going in the mountains. Even reaching trailheads will be difficult. Natural avalanches could be large and destructive. They may come from overhead in terrain that's out of view. Weather and travel conditions will make for a challenging and miserable day. 

    Rain and heavy snow will fall on a weak snowpack. The upper snowpack is very light and dry and will quickly become unstable with rain. You can find strong-over-weak layering 2 feet below the new/old interface. Small facets and surface hoar in the upper snowpack, could easily break under the load of the storm. Depending on how the storm progressess, wet avalanches may be smaller below treeline, though you're still likely to encounter them there.

    (1/21/2022)

    An example of wet slab avalanche from last season. Stevens Pass Mountian Resort,  closed terrain.

    Photo: Matt Primomo

Avalanche Discussion

The current storm will bring warmer temperatures with wet snow and rain (liquid or freezing). Stay tuned for any changes as this is a challenging forecasting scenario.

On the 18-20th, Stevens Pass picked up cold, dry snow with 3-day 24-hour totals reaching nearly 3 feet. The December 18th interface holds weak grains of small facets, surface hoar, and crusts on southerly aspects. I found easy, sudden shears in snowpack tests on this interface on Monday. You may also find the December 8th surface hoar layer another foot lower in the snowpack. Weak layers, buried in late November, can be found near the bottom of the snowpack around a couple of crumbly crusts. While they haven't been involved in avalanches in over a month, a very big storm could activate them.

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