Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

MODERATE avalanche danger exists on steep slopes at all elevations due to wind slabs formed during the storm and new wind slabs formed by the NE and E winds today. Human-triggered wind slab avalanches will remain possible today. Identify areas where wind slabs may exist and plan backcountry travel routes to avoid wind-loaded slopes.  

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Human-triggered wind slab avalanches will remain possible on wind-loaded slopes 35 degrees and steeper today. As the winds shift to the east and increase, some new wind slabs will form on NW-W-SW-S-SE aspects. These new wind slabs should remain small and not extend very far from ridgelines unless wind speeds climb higher than forecasted. These east winds will strip some snow away from the wind slabs that formed during the storm, but these older wind slabs will still linger on many NW-N-NE-E-SE aspects. In some areas, these may become hard slabs that could break above a person on the slope. The largest and most fragile wind slabs will exist on wind-loaded near and above treeline terrain, but wind slabs may still be possible in some exposed below treeline areas as well. Large unstable cornices exist above many wind-loaded slopes. 

    Looks for signs of recent wind-loading such as cornices, blowing snow, wind drifts, wind pillows, ripples on the snow surface, and other wind created textures to help identify where wind slabs may exist and use this information to avoid areas with possible wind slabs.

Avalanche Discussion

Observations yesterday on Andesite Peak and Powderhouse Peak found up to 18 inches of new snow sitting on top of wet rain-soaked snow from earlier in the storm. Snowpit data and observations in sheltered terrain on Powderhouse Peak and on exposed wind-loaded terrain on Andesite Peak showed a right side up snowpack with more dense snow near the base of the storm snow and lighter snow near the top. On Andesite Peak, ski cuts and ski kicks triggered some shooting cracks on wind-loaded test slopes, but neither ski cuts nor large cornice pieces dropped onto test slopes produced wind slab failures. 

Regions covered