Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
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Pericolo valanghe

Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 12 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Near and above treeline, avalanche danger remains MODERATE on NW-N-NE-E-SE aspects on slopes 35 degrees and steeper due to ongoing concern for human triggered wind slabs. For all other areas, avalanche danger is LOW.

Problemi valanghivi

  • Wind Slabs

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

    New wind slabs that formed during the past 24 hours are expected to remain unstable today. Human triggered wind slabs up to 2 feet deep are possible in areas along the Sierra Crest. Smaller wind slabs 6 to 18 inches deep are expected in other areas. Pick and choose wisely when dealing with wind loaded NW-N-NE-E-SE aspect slopes steeper than 35 degrees. Wind slabs are avoidable by studying the snow surface and identifying areas that are vs. areas that are not wind loaded. Evaluate consequences of getting caught in an avalanche in terms of potential impact with trees or deep burial in terrain traps. Travel one at a time in avalanche terrain, moving from one high quality island of safety to the next. These types of simple hazard recognition, informal information gathering, and deliberate informed decision making are a big part of the difference between "getting lucky" and "getting it done" in the backcountry.

Avalanche Discussion

Observations made yesterday on Mt. Judah's Wildflower Ridge (Donner Summit area) revealed that easily human triggered wind slabs had formed in wind loaded areas by noon. Skier triggered wind slabs propagating up to 40' wide were noted on NE aspect test slopes at 7,800' with slab depth at that time of 4 to 10 inches. These wind slabs were failing on a weak layer of lower density storm snow at the base of the wind slab. No evidence of buried surface hoar was observed in wind protected locations in the area. Additional observations received from the Mount Rose area indicated smaller, significantly less sensitive wind slabs had formed in wind loaded areas along ridgelines. No evidence of buried surface hoar was noted in that area either.

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