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 continues to be possible throughout most of the forecast area due to persistent slabs.  These persistent slabs are found on slopes steeper than 32 degrees at all elevations mainly along the Sierra Crest.  Human triggered avalanches remain possible today. 

Avalanche problems

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Persistent slabs continue to remain possible due to persistent weak layers found near the Dec. 15 rain crust.  In most areas, but not all, near crust facets are the primary persistent weak layer formed above the Dec. 15 rain crust and are now buried under the most recent storm snow.  There is variability as to where these persistent slabs exist, they have been found to be mostly along the Sierra Crest on W-NW-N-NE-E aspects at all elevations.  Where deeper snowpacks exist at higher elevations in the Mt. Rose area, this persistent slab avalanche problem has been found to be unlikely.  Recent snowpack tests along the Sierra Crest continue to show weakness around the Dec. 15 rain crust and that propagation is likely if this weak layer could be triggered.

    Persistent slab avalanches are unpredictable and require different terrain management techniques.  These avalanches could be triggered low on a slope and away from what we think of as traditional ridgetop wind slab start zones.  Wide propagation is possible into connected terrain.  Use conservative decision making and travel techniques. 

Avalanche Discussion

Observations were received yesterday from Red Lake Peak (Carson Pass area) and Polaris Point (Ward Canyon area).  Both locations showed snowpack tests failing near the Dec. 15 rain crust on persistent weak layers.  Snowpack tests continue to show that propagation is likely if these weak layers can be triggered.  A high level of variability exists even in one area as to where these weak layers exist and where they don't.  On Polaris Point, a shallow and variable snowpack existed below 7800'.  On Red Lake Peak, some evidence of recent warming related loose wet activity existed.  At both locations, wet and sticky surface snow was found on southerly aspects by mid day.

Regions covered