Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

HIGH avalanche danger will continue as a powerful winter storm impacts our forecast area today and through tonight.  Very dangerous avalanche conditions will exist.  Travel in, near, or below avalanche terrain is not recommended.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2

    Gale force SW winds along with additional snow today and tonight will add to existing fragile wind slabs and cornices from yesterday.  Large and destructive wind slab avalanches will be very likely on NW-N-NE-E-SE aspects in near and above treeline terrain.  Wind slabs could also form on other aspects and in below treeline areas due to the elevated SW wind speeds.  Large wind slab avalanches could occur naturally and travel far distances down into mature forests.  Travel in, near, or below avalanche terrain is not advised. 

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2

    Storm slab avalanches will be very likely on all aspects in near and below treeline terrain.  High intensity snowfall rates of 3''/hour or more are forecasted during this storm today and tonight.  Weaknesses could develop within the new storm snow today or snow that fell during the last 2 days.  Avalanches that involved deeper layers in the storm snow, or the potentially buried surface hoar layer, would be much larger in size and have severe consequences.  Large and destructive storm slab avalanches that occur naturally could run long distances through mature forests.  Travel in, below, or near avalanche terrain is not recommended.

Avalanche Discussion

*  Storm slab and wind slab avalanches were reported from Incline Lake Peak (Mt. Rose area).  Widespread instabilities were noted with large shooting cracks and wind transport.  Storm slab avalanches up to size D2 were reported from ski cuts.

*  Wind slab avalanches were easily triggered on small test slopes on Tamarack Peak (Mt. Rose area).  Large shooting cracks, intense wind transport, with limited visibility was observed.

*  Other signs of instability were reported from Shirley Canyon (Squaw Valley area), Powderhouse (Luther Pass area), and Meadow Lake (Independence Lake area).  Moderate to intense snow transport, shooting cracks, and wind slab development were all observed.  Some protected below treeline areas showed little signs of instabilities.

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