Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

Wednesday should be another mellow day in the mountains. However, you may still be able to trigger an avalanche in wind drifted snow at higher elevations. The base of cliffs, very steep ridges, and confined chutes are the most likely areas to find these pockets of unstable snow. Firm, hollow-sounding snow or shooting cracks are indications that you could trigger an avalanche if you venture onto steeper terrain. 

Problemi valanghivi

  • Wind Slabs

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

    Wind slabs may still linger near ridgelines, the base of cliffs, in confined gullies, or on convex features in alpine terrain. Easterly winds over the weekend shifted west in the early hours of Monday. The shift in wind direction means you could find these pockets of unstable snow on most aspects. Very steep, rocky, ridgeline terrain is the most likely place to encounter this problem. Use visual clues to identify wind-affected snow, such as drifts, cornices, or rippled snow surfaces. You can use your probe, pole, or quick hand pits to identify stiff wind-driven snow over softer snow layers. Travel cautiously in consequential terrain where even small avalanches could push you over cliffs or exposed rocks. 

    (12/3/2022) This wind-blown snow likely collected near the base of the cliffs and rocks seen in the foreground. Photo: Dallas Glass

Avalanche Discussion

The past week brought 30 inches of snow to Snoqualmie Pass, significantly increasing coverage throughout the zone and making travel possible at lower elevations. Over the weekend, winds then drifted the new low-density snow into slabs. Multiple reports indicated people triggering wind slabs, with a couple of instances where individuals were caught and carried. Luckily, as far as we know, no one was injured in one of these slides. Even though the recent snow has improved travel conditions and coverage at lower elevations, it still feels like an early season shallow snowpack. As you venture out for winter recreation, you will still have to contend with plenty of trees, shrubs, and open creeks. Travel cautiously and consider the consequences in terrain where smaller avalanches could drag you through these natural hazards. While the snowpack in the Snoqualmie Pass area is generally strong with various crusts and rounded grains, other zones harbor a weaker snowpack structure with sugary faceted snow layers under this past week's storm snow. It's still early season, and we are gathering more information on snowpack variability throughout the zone. These deeper weak layers could exist in areas of the zone where we lack observations.

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