Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Our current storm continues today with more heavy wet snow and strong winds.  In areas that have weak sugary snow near the base of the  snowpack, this heavy snow will add additional load with the potential for large avalanches.  Strong winds will continue to form slabs of wind blown snow in open areas.  Dangerous avalanche conditions could exist today.  

Avalanche problems

  • Wind Slabs

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

    Gale force SW winds have created wind slabs in near and above treeline areas during this storm and will continue today.  Areas that have received the most snow in the southern portion of the forecast area, will have wind slabs larger in size.  Wind slabs are expected to form in near and above treeline areas along ridges, in gully features, and in open areas.

    Blowing snow, cornice formation, wind pillows, and snow surface scouring will all be clues as to where these wind slabs are forming.  Identify where wind slabs may exist and move around areas of concern. 

    (11/25/2024)

    Large cornices building out along with wind slabs.  Mt. Judah, Donner Summit area.

    Photo: Sierra Avalanche Center

  • Persistent Slabs

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

    Weak faceted snow that formed earlier this season continues to exist on NW-N-NE-E aspects above 8000-8500'.  This persistent slab avalanche problem extends into above treeline areas in isolated locations.  We have had 1 confirmed large avalanche on this weak layer, 1 unconfirmed avalanche, slope scale collapses, shooting cracks, and whumpfing sounds over the last few days.  The heavy wet snow we are now receiving will continue to add additional load to this weak layer making avalanches more likely, especially in areas that are receiving the higher end snow totals with this storm.  Recent rain has strengthened this weak layer below 8000'.

    This avalanche problem exists in very specific terrain, with the best management technique being avoidance if traveling in these areas.  Recent avalanches, collapses, shooting cracks, and whumpfing sounds, will all be signs that this weak layer is active in your area.  Remote triggering is possible along with avalanches occuring mid-slope or even low on the slope.  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

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