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

In sintesi

A wind slab avalanche problem is expected to continue today in near treeline and above treeline areas. MODERATE avalanche danger exists near and above treeline. LOW avalanche danger exists below treeline.

Problemi valanghivi

  • Wind Slabs

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

    Yesterday's strong SW winds created blowing and drifting snow near and above treeline. Unstable wind slabs existed yesterday with avalanche activity reported in lee areas. A wind slab avalanche problem is expected to continue today with human triggered avalanches possible. The vast majority of wind slabs exist near treeline and above treeline on NW-N-NE-E-SE aspects. Expected avalanche size is up to D2. As winds shift to the NE tonight, new wind slabs may form on SE-S-SW-W-NW aspects.

    Identify the specific features of concern where wind slabs exist and move conservatively around them. Read the terrain by identifying cornices, wind pillows, and the textured snow surfaces associated with recent wind drifted snow and wind slab formation. Softer snow and less avalanche hazard will be found in the wind protected areas below treeline, but maintain awareness of exposure to steeper slopes overhead that hold wind slabs.

Avalanche Discussion

* SW ridgetop winds were much stronger than forecast yesterday, leading to more blowing snow and wind slab avalanche activity than expected.

* Natural and human triggered wind slab avalanches up to size D2 were reported yesterday from the Carson Pass, Echo Summit, and West Shore Tahoe areas. These avalanches occurred in near treeline to above treeline terrain mainly on N-NE-E aspects. Observations also indicated unstable wind slabs on Silver Peak (Pole Creek area). In the Carson Pass and Pole Creek areas, observers noted that the weak layer was lower density snow below the wind slab. 5 people were reported caught in avalanches yesterday (4 in an avalanche on Echo Peak and 1 in an avalanche on Melissa Coray Peak).

* No signs of instability were reported from wind protected areas below treeline.

 

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