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 12 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

In response to daytime warming, avalanche danger will quickly rise from to LOW danger early this morning to MODERATE danger later this morning for all elevations and aspects on slopes 37 degrees and steeper. Human triggered loose wet avalanches will become possible. Natural avalanches remain unlikely.

Problemi valanghivi

  • Loose Wet

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

    As daytime warming progresses, the poor to decent snow surface refreeze that occurred last night will transition from supportable crust to deep wet snow. Partly cloudy skies last night will have limited the potential for radiational cooling. The best snow surface refreeze will have occurred in areas where air temperatures were actually below freezing. Once the surface refreeze melts and the snow surface becomes unsupportable, enough unconsolidated wet snow will exist for human triggered pinwheels, roller balls, and loose avalanches to become possible on all aspects at all elevations.

Avalanche Discussion

Observations made yesterday in Poison Canyon and on Mt. Reba (Bear Valley Backcountry) revealed a poor overnight refreeze and a rapidly melting snowpack on SE-S-SW aspects. Snow surface conditions consisted of a weak 1 inch thick melt freeze crust during the early morning hours that quickly gave way to breakable crust and then deep wet snow over the course of about 30 minutes. Many areas of bare ground existed on SE-S-SW aspects between 7,600' and 8,700'. On NW-N-NE aspects the snowpack remains 3 to 6 feet deep. On the N side of Mt. Reba, many areas of naturally triggered cornice collapse had occurred, with no evidence of recent slab avalanche activity.

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