Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

HIGH avalanche danger continues in near treeline and above treeline areas due to a wind slab avalanche problem. CONSIDERABLE avalanche danger continues below treeline due to a storm slab avalanche problem and isolated wind slabs. Natural and human triggered avalanche activity is expected. Travel in near treeline and above treeline avalanche terrain is not recommended.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2

    Wind slabs are widespread following new snow combined with gale force SW winds. The vast majority of wind slabs exist near treeline and above treeline on NW-N-NE-E-SE aspects. Unstable wind slabs may be encountered to a more isolated extent on other aspects and below treeline due to the strength of the wind. Avalanche size is expected mostly at D2 with up to size D3 possible.

    If traveling below treeline, expect that avalanches from above may run into below treeline areas. Pre-plan for low visibility obscuring avalanche start zones overhead. Move around avalanche runout zones with a wide, conservative margin. Do not underestimate potential avalanche size and runout distance.

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1

    High intensity snowfall this morning and rising snow level today will continue to provide the ingredients for a storm slab avalanche problem.  Unstable storm slabs are likely on any wind protected aspect in below treeline to near treeline terrain. Avalanche size up to D2 is expected.

    All slopes are suspect at this time and careful, independent evaluation is necessary before making a decision to enter below treeline avalanche terrain. Expect avalanche activity today and be aware of lower angle slopes connected to steeper slopes above or to the side. Get out of existing tracks and gather data. If signs of snow surface cracking or recent avalanche activity are present, make conservative decisions and avoid avalanche terrain.

Avalanche Discussion

* A natural storm slab avalanche with a crown up to 3 feet occurred yesterday morning below treeline on Andesite Peak (Donner Summit area) (more info).

* Intense blowing snow was observed well below treeline yesterday on Powderhouse Peak (Luther Pass area).

* Wind slabs were present yesterday in most all wind loaded areas but were difficult to trigger in the limited number of areas tested.

* Large fragile cornices were observed yesterday near Picnic Rock (Brockway Summit) and along the summit ridge of Andesite Peak (Donner Summit area). Some of these collapsed from triggers 15 to 20 ft back from the edge.

Regions covered