Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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

A major Pacific storm will impact our forecast region tonight through Thursday.  HIGH avalanche danger will exist at all elevations throughout the night due to wind slab and storm slab avalanche problems.  Travel in, near, or below avalanche terrain is not recommended.

Avalanche problems

  • Wind Slabs

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

    High intensity snowfall tonight along with gale force SW winds will create large and fragile wind slabs on NW-N-NE-E-SE aspects in near and above treeline terrain.  Wind slabs could also form on other aspects and in open below treeline areas.  Large and destructive natural wind slab avalanches could travel long distances into below treeline terrain.  

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

  • Loose Dry

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

    Storm slab avalanches will be likely overnight on all aspects in wind protected near and below treeline terrain.  Snowfall intensity is forecasted to reach 3+'' an hour along with potential rising temperatures into the morning creating upside down storm snow.  Weaknesses could occur within the new storm snow or at the new snow/old snow interface.

     

Avalanche Discussion

*  Yesterday, a small natural wind slab avalanche (D1) was reported on the east bowl of Mt. Judah (Donner Summit area) in open above treeline terrain.  A small skier triggered wind slab avalanche (D1) was unintentionally triggered on the NW side of Castle Peak (Donner Summit area).  In Johnson Canyon (Donner Summit area) an intentionally triggered wind slab avalanche failed on a small test slope.

*  Strong to gale force winds reported throughout the forecast region with intense blowing snow at most locations.  Areas of firm exposed crusts are present in many wind scoured locations.

*  Snowpack tests targeting the Feb 14 rain crust at Polaris Point (Carson Pass area) showed sudden planar results on a graupel layer buried 120cm down on top of the rain crust with the Deep Tap test.  Snowpack tests today on Peak 9269' (West Shore area) on the graupel layer above the Feb 14 rain crust showed no unstable test results with the ECT, CT, and DT tests.

Regions covered