Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 8 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Increasing winds and rising snowlines will cause avalanche danger to rise throughout the day. Newly formed wind drifts will continue to build and become more sensitive—watch for wind-textured or heavier snow and avoid steep slopes where it is present. As rain moves higher, small wet avalanches may occur.

Problemi valanghivi

  • Loose Wet

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

    Rain will gradually move into the mid elevations, increasing the chance of wet loose avalanches at lower—and possibly mid—elevations. Most activity should stay in surface layers, but a wet loose slide could step down into a larger slab.

    Pay attention to precipitation type and surface conditions. If snow becomes wet and sticky or you see rollerballs on steep slopes, move to lower-angle terrain. Wet avalanches are most likely near rocks and beneath trees, where falling tree bombs will be common on Wednesday.

    Example photo: Small rollerballs could indicate wet loose avalanche may follow.  Photo: Andrew Kiefer

  • Wind Slabs

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

    Wednesday will feel very different from Tuesday. Strong east/southeast winds and a few inches of snow falling during the day will redistribute snow into thick slabs in unusual locations, possibly further downslope and on different aspects than you're used to. Danger will increase as you gain elevation into more wind-exposed slopes, and beware that places you traveled earlier without slabs could have developed reactive slabs later on. 

    Identify actively drifting snow, and avoid those areas on steep slopes. Drifts tend to form on the leeward side of ridges, around features, and in gullies. Search for "red-flag" signs of instability, such as recent avalanches, blowing snow, and cracks shooting through the snow. Steer around cornices and wind-loaded pillows on steep slopes.

    Example photo: Signs of wind loading to look for.

Avalanche Discussion

We've received about 4 inches of water, or up to 4 feet of snowat the mid and upper elevations, over the last significant crust in the West Central zone. This 12/18 crust, in the West North zone where conditions are similar, has a favorable snowpack above it, where snow is softer on top and progressively harder as it approaches the crust. Where we've dug in the West North zone, snow is well bonded to the crust. There are a few suspect failures on the crust, however, in the Stevens Pass zone.

On-the-ground observations in West Central remain sparse due to shallow snow cover and access challenges from recent washouts and landslides. Be prepared to assess the actual avalanche danger for yourself as you climb into snow-covered terrain. Variations in precipitation and new snow amounts, and temperatures can result in markedly different conditions within a single forecast zone.

State and local resources are working diligently to reduce the impacts of destructive storms that occurred earlier this month. We can help by respecting affected communities, complying with road closures, and adhering to ski area uphill travel policies.

Regioni coperte