Bollettino valanghe

East Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

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

Both wet and dry avalanches should be on your mind for Wednesday. At upper elevations, winds may form unstable slabs of snow. Consider steering around steep slopes where you find shooting cracks or active drifting. Don't linger beneath sunny slopes with steep rocks and cliffs that could still shed blocks of wet snow. 

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Strong ridgeline winds may form a fresh round of wind slabs overnight into Wednesday morning. This problem will likely be isolated to the upper elevations along sharp alpine ridgelines. So, if you're headed into the higher elevations, look for actively blowing snow or cracking in wind-stiffened surfaces to indicate a higher likelihood of triggering an avalanche. Corniced ridgelines, confined gullies, and the base of cliffs are all likely places to find fresh wind slabs. We expect most avalanches to be small. However, wind slabs may form over slick to weak surfaces and break wider than expected. Dig down and frequently assess the recent snow using small test slopes and quick hand pits. If you find the snow slides easily, back off steep terrain objectives and choose lower-angle slopes.

    (4/13/2021)

    Blowing snow off of ridgelines, like in this photo, is a good indication of fresh wind slab formation. 

    Photo: Will Govus

  • Loose Wet

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

    After a few days of warmer temperatures and sun, most wet avalanches have already run, and steep southern slopes have a surface crust, further limiting widespread wet loose avalanche concerns. Instead, you should watch for overhead hazards from steep, rocky terrain or cliffs in the sun that could still shed large chunks of snow. Limit your time beneath these suspect terrain features, especially in the afternoon. If the sun and warm temperatures break down surface crusts on southern aspects, you may also be able to trigger small, loose wet avalanches in steep terrain.

    (2/23/2024)

    These steep rock faces in the sun are prime examples of overhead hazards that may still shed snow on Wednesday. 

    Photo: Matt Primomo

Avalanche Discussion

Tuesday turned out to be a bit cooler and cloudier than anticipated. Since we escaped the big warm-up, there could be modest amounts of dry snow at upper elevations that moderate ridgeline winds could drift around. We don't have much information from the upper elevations, so there is some uncertainty about how much snow is available to form wind slabs. If you find deep, dry snow and active wind transport, expect avalanches to be larger.   

Winds and cloud cover should decrease throughout Wednesday, and it should be a breezy but mostly sunny, pleasant day in the mountains. 

On Sunday, an NWAC forecaster in the Salmon La Sac area reported widespread natural avalanche activity throughout the terrain. Lower elevations saw many wet loose and wet slab avalanches, and ridgelines were peppered with an abundance of small crowns. These avalanches were primarily small, likely involving just the recent snow. Observers in the Wenatchee Mountains near Mission Ridge and Blewett Pass found buried surface hoar below the most recent snow. Stability tests have produced inconsistent results, but we expect this layer to be the culprit in the many avalanches seen in the Salmon La Sac area on Sunday. Dig down and identify this persistent weak layer before committing to steep terrain. If you find the telltale grey line of feathery grains buried in the snowpack, consider sticking to more conservative terrain since these layers can be reactive long after the last storm. 

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