Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Increasing winds are blowing and drifting snow on the ground, potentially creating unstable avalanche conditions in areas where blowing snow has accumulated.  Exercise caution near or below slopes where blowing snow is accumulating, snow surface cracking is occurring, or recent avalanches have occurred. Triggering a very large avalanche very deep within the snowpack has become unlikely but is not impossible from large triggers such as cornice collapse or the landing of jumps off of cornices, rocks, or cliffs.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Increasing SW winds are blowing, drifting, and redistributing snow on the ground from one side of the ridgetops to the other. This will create new wind slabs in areas where this blowing snow deposits, mainly above treeline and near treeline on NW-N-NE-E-SE aspects.

    Identify and move cautiously around slopes where there is visible blowing snow, slopes that are below cornice formations, on snowcovered slopes with wind textured snow surfaces, or near any areas where snow surface cracking is occurring. 

    (12/18/2021)

    Small skier triggered wind slab avalanche with partial burial on Stevens Peak, CA. NE aspect near treeline terrain around 8,600'.

Avalanche Discussion

*Snowpack data suggests that triggering a persistent slab avalanche on old layers of weaker snow 4 to 5+ feet deep in the snowpack is unlikely due to isolated lingering weak layer distribution and difficult (stubborn) triggering. Forecast guidance directs removing persistent slabs as an avalanche problem once likelihood decreases to unlikely. Unlikely is not impossible so the savvy things to do right now as a backcountry traveler are to avoid traveling near exposed rocks where the old weak layers could be closer to the snow surface and avoid creating large impacts on slopes from actions such as jumping off of rocks, cliffs, or cornices.

*Surface hoar has been observed in numerous locations around the forecast area especially at low to mid elevations. The question for this potential future weak layer is if it persists to burial or is destroyed by wind and warming leading into the next storm event on Tuesday.

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