Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

Triggering a large avalanche 2 to 6+ feet deep remains possible today where weak snow is buried below the snow surface.  These avalanches could be triggered from low angle areas above, below, or from off to the side of steeper avalanche terrain.  Signs of unstable snow may not be obvious today in the backcountry.  Today’s avalanche problem still warrants conservative decision making and terrain choices.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    Persistent weak layers continue to exist on various aspects and elevations throughout the forecast region.  The Jan. 2 persistent weak layer includes buried surface hoar, near surface facets, and/or a facet/crust combo and has been responsible for the majority of our recent avalanche activity.  The Dec. 19 rain crust and basal depth hoar on the ground have also been reported of failing on some avalanches that have stepped down to these lower weak layers.  With each passing storm, these weak layers become buried deeper in the snowpack.  Areas where these weak layers are closer to the surface; steep rocky slopes, complex terrain,  any shallow snowpack areas, may be more likely locations to trigger a persistent avalanche.

    People can remotely trigger these avalanches from above, below, or to the side of a slope, and they often break much wider than expected.  Recent avalanches, snow surface cracking, snowpack collapse, or whumpfing sounds indicate unstable persistent slabs, but fewer obvious clues may exist today.  Utilizing non-avalanche terrain, with no steeper connected slopes above you, can greatly reduce your exposure to this avalanche problem.

    (1/15/2024)

    Large natural avalanche between Lincoln and Anderson Peak-thought to have occurred on Sat Jan 13.  See the size of the crown relative to the people.

Avalanche Discussion

The Jan. 16-17 storm rained up to at least 8500', if not much higher.  Up to 4'' of heavy wet snow accumulated in some areas of the forecast region either on top of this rain crust or at the higher elevations above 8500-9000'.  Gale force SW winds yesterday scoured what little snow was present on all exposed terrain back down to the rain crust.  Limited available snow for transport made for limited wind slab formation.  The firm rain crust will make for challenging travel conditions on most terrain up to around 8000-8500'.   

Regions covered