Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 5 years ago.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

Highlights

Avalanches of loose wet snow may become possible on steep sun-exposed slopes due to daytime warming. Cornice failures may also be possible. The avalanche danger will increase from LOW this morning while the snow remains frozen to MODERATE as the day warms up and the snow becomes wet.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Clear night skies should have allowed yesterday's wet snow to refreeze despite overnight temperatures at or above freezing in many areas above 7000 ft. The strong SW winds and predicted afternoon cloud cover should slow down the formation of wet snow today, but the March sunshine and warm daytime temperatures should still provide enough warming to form wet snow on sun-exposed slopes. In areas with the most warming, some loose wet avalanches may become possible. Steep sun-exposed slopes or areas around rocks, cliffs, and gully features that absorb more solar radiation represent the likely areas for loose wet instabilities to occur. 

    The snow on sunny slopes will go from firm frozen crusts to shallow wet snow to deeper wet snow as the day warms up. Step off your equipment on a regular basis to check the depth of wet snow. If you sink into wet snow above your ankle, it's time to move to colder aspects or terrain less steep than 30 degrees. 

    (3/2/2021) Small skier triggered loose wet avalanche on Incline Lake Peak. SE aspect, 8600', at 12pm.

  • Cornices

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

    The warm weather is also weakening the cornices that exist along many ridgelines. Large pieces that could injure a person could break off of these overhanging waves of snow as they melt.

    Cornices often break farther back from their edges than expected or at unexpected times. Staying far away from the edges of cornices and not traveling underneath cornices can help avoid this problem.

    (3/4/2021) Previous cornice failure in Johnson Canyon

Avalanche Discussion

Melt-freeze conditions exist on many SE-S-SW aspects below about 8500'. The snow on most E and W aspects and elevations above 8500' has not experienced as much melting and refreezing and is still transitioning to supportable spring melt-freeze conditions.

* Pockets of unconsolidated soft snow still linger on some northerly aspects in wind-protected below treeline areas. Some of the snow around the rain crusts near the surface of the snowpack has started to weaken (facet).

* Large cornices exist along many ridgelines.

* Exposed rain crusts, melt-freeze crusts, and wind-scoured surfaces can be encountered on any aspect and elevation.

Regions covered