Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 7 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Welcome to winter. CONSIDERABLE avalanche danger exists in near treeline and above treeline areas due to wind slabs. MODERATE avalanche danger exists below treeline due to the possibility of storm slabs. Snowcover is thin and there are lots of rocks to hit. Travel with care. This is a 48 hour forecast to cover Wednesday and Thanksgiving day. The next update will occur on Friday by 7 am.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1

    Wind slabs are likely today and Thursday, created by the moderate to gale force SW winds that have drifted snow along the ridgetops and other wind exposed areas. The vast majority of winds slabs will exist in near treeline and above treeline terrain on NW-N-NE-E-SE aspects. Expected avalanche size is up to D2. Use clues such as blowing snow, pillows of drifted snow, signs of cornice formation, and areas of deeper, denser snow to identify where wind slabs exist and route find around them. 

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    New snow that accumulates today and Thursday will do so under more variable conditions. This will allow for a greater chance of storm slab formation than just new snow on bare ground. The possibility of storm slab avalanches will become more widespread in wind protected areas below treeline on all aspects today and tomorrow. There is also a small chance that locations on the east side of the forecast area where new snow was deposited on top of a thin layer of moderately faceted (sugary) snow leftover from the Nov 19-20 snowfall may be problematic. Signs of snow surface cracking or collapsing in wind protected areas below treeline indicate the presence of unstable storm slabs in the immediate area. Avalanche size is expected at D1 with the isolated possibility of a size D2.

Avalanche Discussion

Prior to this storm, most locations within the forecast area were bare ground. Some areas of patchy, moderately faceted (sugary) snow 1 to 3 inches deep lingered along the eastern edge of the forecast area on NW-N-NE aspects. Most of this snow was in wind protected areas at and below treeline.

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