Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Sat
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

High intensity snowfall with strong winds will continue today.  Large cohesive slabs of wind-blown snow and deep slabs of new storm snow will exist in the backcountry.  HIGH avalanche danger is expected today-travel in avalanche terrain is not recommended.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1.5–3

    Gale force SW winds yesterday with 1 to 1.5 feet of new snow built out wind slabs on NW-N-NE-E-SE aspects in near and above treeline areas.  These wind slabs will continue to grow today as additional snow and winds impact our region.  Another 1 to 1.5 feet of additional snow is possible for today with continued strong to gale force winds.  Some wind slabs could exist in other locations in below treeline terrain due to the recent strength of the winds.  Wind slab avalanches could be both natural and human triggered today with the potential for large cornice collapses.  These avalanches could run long distances down into mature forest. 

    Travel in, around, or below avalanche terrain is not recommended today.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2.5

    A winter storm that began Tuesday afternoon has brought multiple feet of snow to our mountains.  Due to the convective nature of the snowfall, some areas have received much more snow than others.  Several layers of graupel exist throughout this storm snow that may fail under additional load.  High intensity snowfall expected today could also overload these layers and cause storm slab avalanches to occur.  Storm slab avalanches could occur on any aspect in near and below treeline terrain.

    Travel in, near, or below avalanche terrain in not recommended today.

Avalanche Discussion

Recent Observations:

  • Limited observations were available from Thursday due to the snowfall intensity, strong winds, and low visibility.
  • Layers of graupel exist throughout the recent storm snow and may contribute to instability as a potential weak layer.
  • Some layers of old graupel, facets, and/or buried surface hoar can be found about one to two feet below the snow surface on some NW-N-NE aspects. For the most part, these layers are well bonded into the snowpack. It is unlikely that the amount of low density new snow load that occurs this week will overload these layers.

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