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
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 13 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Early this morning, avalanche danger is LOW for all elevations and aspects. As the day progresses, areas of MODERATE danger will form on all aspects at all elevations on slopes 37 degrees and steeper in response to daytime warming. Small human triggered loose wet avalanches will become possible.

Problemi valanghivi

  • Loose Wet

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

    A decent snow surface refreeze is expected to have occurred last night due to near or below freezing air temperatures and radiational cooling of the upper snowpack under clear skies. As daytime warming progresses, surface wet snow instability will develop. Human triggered loose wet avalanches will become possible from late morning onward, especially during the afternoon and evening hours. Most areas of instability will exist on E-SE-S-SW-W aspects, spreading to include areas on NW-N-NE aspects later in the day. With many previous melt-freeze cycles and previous rain events having already occurred this winter and spring, free water drainage from the snowpack is well established. This is expected to keep loose wet avalanche activity limited to human triggered avalanches that are relatively small in size.

Avalanche Discussion

Observations made yesterday on Tamarack Peak (Mount Rose area) revealed that snow level Wednesday night had been around 8,300' in that area. Minimal new snow amounts of a trace to nearly 1 inch of new snow had accumulated. By mid day, this new snow was quickly assimilating with the melt-freeze snow below on all but true north aspects above 9,500'. At 1 pm, a very small and very minor intentionally skier triggered loose wet avalanche occurred on the E aspect Proletariat Face at 9,700' in a pocket of 40 degree slope angle near treeline terrain (photos, more info). The avalanche involved only the top 1 inch of the snowpack, but indicated that a few more inches of wet surface snow could become involved in human triggered loose wet avalanches later in the afternoon and evening hours.

Regioni coperte