Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Avalanche danger is expected to gradually increase today. The areas of greatest danger are expected to occur this afternoon along the Sierra Crest. New snow, wind, and new slabs forming on top of surface hoar could make for unstable conditions today if this storm performs to its potential. Exercise caution and consider avoiding avalanche terrain in locations where new snow amounts meet or exceed 4 to 6 inches.

Avalanche problems

  • Wind Slabs

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

    New snow will be drifted by gale force SW winds today and deposited on the downwind side of ridgetops and into gully features. This drifted snow is expected to form cohesive slabs. Slab thickness will be very dependent on the amount of new snow we receive today. In any areas where fresh slabs of wind drifted snow form on top of surface hoar, wind slab avalanches could be wider than expected. A wind slab on top of surface hoar is most likely to form near treeline across NW-N-NE aspect terrain.

    Identify and consider avoiding avalanche terrain in areas where wind drifted snow is depositing. Use clues such as visible drifting snow, wind drifts, cornice formations, snow surface cracking, and snow surface texture to highlight areas of concern.

     

    (2/9/2024)

    Lots of visual clues for recently wind drifted snow and the potential location of wind slabs in this picture. Mt. Tallac, CA. Photo: Public

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Large surface hoar has persisted in avalanche terrain across NW-N-NE aspects near treeline and to an impressive extent below treeline. If this storm performs today, unstable storm slabs are possible across these northerly aspects in locations where 4 to 6 inches or more of new snow is deposited on top of surface hoar. If this occurs, anticipate shallow, wide failing storm slabs today. If this storm underperforms, then the surface hoar will be preserved in the upper snowpack as a weak layer, waiting for the next storm cycle to contribute to avalanche activity.

    Look for areas of snow surface cracking in wind protected areas. If you are triggering any snow surface cracking, move cautiously around nearby avalanche terrain. 

    (2/24/2024)

    10 to 15 mm surface hoar was observed persisting top to bottom through this below treeline avalanche path and in the thicker treed terrain on either side. N aspect, Ophir Peak, NV.

    Photo: Sierra Avalanche Center

Avalanche Discussion

Across open E-S-W aspects slopes surface hoar was destroyed by melt. A melt-freeze crust now exists at the old snow surface across these aspects. Small sluffs of new snow are possible today on top of this crust in steep terrain.

Regions covered