Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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

An approaching storm will impact our forecast region starting today with heavy snow and strong winds.  In areas where weak snow continues to exist near the base of the snowpack, large avalanches remain possible as extra load gets added to these weak layers.  Strong winds will also create slabs of wind blown snow in open areas.  Avalanche danger is expected to quickly rise to CONSIDERABLE this evening, as the storm intensifies.  

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    A persistent slab avalanche problem continues to exist on NW-N-NE-E aspects, above 8000-8500' in mostly near and below treeline areas.  This faceted snow formed near the ground and around crusts from earlier storms in October.  Recent rain has strengthened this weak layer below 8000'.  This next storm starting later today will add additional heavy snow on top of this weak layer and could reactivate it.  Large avalanches, slope scale collapses, shooting cracks, and whumpfing sounds have all been reported over the last few days associated with this weak layer.  

    Recent avalanches, collapses, shooting cracks, and whumping sounds will all indicate that the weak layer is active.  This avalanche problem exists in very specific terrain, with the best management technique being avoidance if traveling in these areas.  Avalanches could be triggered mid-slope or even towards the bottom of slopes.  Avalanches on this weak layer could be large in size with increased consequences due to the early season conditions.  

    (11/24/2024)

     An impressive avalanche ran naturally on the upper bowl on Elephant's Back. The weak layer was sugary facets at the base of the snowpack.  Carson Pass area.

    Photo: David Reichel/SAC

  • Wind Slabs

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

    SW winds are expected to increase today as our next storm approaches.  Gale force SW winds will have some existing available snow for transport, with increased blowing snow as snowfall increases later today.  Wind slabs are expected to form in near and above treeline areas along ridges, in gully features, and in open areas.

    Look for blowing snow, cornice formation, and wind pillows as clues to where these wind slabs are forming.  Cracking or strong over weak snow layering will indicate potential unstable wind slab.  Move around these areas of concern.

Regions covered