Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

Avoid steep slopes where fresh wind-drifted snow is building into slabs. If you notice widespread instability and natural avalanches, the danger is locally higher — so reduce your exposure to wind-loaded slopes overhead.

Problemi valanghivi

  • Wind Slabs

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

    Strong easterly winds will ramp up overnight and last through most of Thursday. East winds tend to have varying effects depending on your location in the forecast zone. Some areas will see strong winds, significant wind transport, and slab formation while others will experience tamer conditions.

    Fresh slabs will form over a combination of crust, faceted snow, and surface hoar. This can result in more reactivity than usual. While most avalanches should be small, some could be larger and possibly step down and trigger an avalanche that releases in deeper layers. 

    You can assess the stability of fresh wind slabs, but the best option will be to avoid steep slopes accumulating wind drifted snow. If you witness extensive wind transport and natural avalanches it might be wise to limit your exposure to big slopes overhead that are loading up.

    (2/12/2025)

    This small wind slab was remotely trigged. It probably formed over a crust topped with a thin layer of facets or surface hoar. Artist Point/West North, south aspect, at 5100'. 

    Photo: Adam Ü

Avalanche Discussion

Wind slab was the name of the game on Wednesday with small human-triggered avalanches reported from multiple forecast zones including West North and Snoqualmie Pass. One small slab on a mid-elevation, south-facing slope was remotely triggered near the Mt. Baker Ski Area.  Strong wind continued through the day in both of the passes with wind slab avalanches triggered far downslope from ridgeline in the Alpental Valley.

Cold dry snow is still found in most shaded and sheltered terrain while crust is found on slopes facing the sun. Continued clear skies and cool temperatures have enabled faceting in the uppermost layers with surface hoar and more faceted snow found topping the snowpack. 

Buried weak layers that produced avalanches two weekends ago have trended more resistant in testing and less likely to propagate. Also, no human-triggered avalanches - that were suspected of releasing at either the 1/31 or 1/10 interfaces - were reported in the last week from the west side of the Cascades.  The layering in question can be found between 1.5-4' deep where the top layers of snow meet a crust or denser layer. We may see more action from these layers as fresh snowfall in the forecast adds additional load. 

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