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

HIGH avalanche danger exists at all elevations. Due to heavy snow, intense snowfall rates, and gale force winds human triggered wind slab avalanches and storm slab avalanches will be very likely today and natural avalanches will be likely. Some avalanches could be large, deep, and destructive. Travel in or near avalanche terrain or in the runout zones of avalanche paths is not recommended.

Avalanche problems

  • Wind Slabs

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

    Large, deep, and widespread human triggered wind slab avalanches are very likely today and natural wind slab avalanches are likely. Heavy snowfall and gale force S and SW winds have and will continue to form larger, deeper, and more widespread wind slabs on wind-loaded W-NW-N-NE-E-SE aspects. The largest and most sensitive wind slabs should exist in near and above treeline terrain and could have crowns deeper than 4 to 6 ft, but some wind slabs may also exist on wind loaded slopes in below treeline terrain. 

    Blowing snow, cornices, wind drifted snow, and other wind created features and textures can help identify where wind slabs may exist. Avoid those areas and the runout zones of potential wind slab avalanches. 

  • Loose Dry

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

    Heavy snowfall with rates of 2+ inches per hour at times and changing conditions during the storm that create slabs and weak layers within the storm snow mean that human triggered storm slab avalanches will become very likely today and natural storm slabs will become likely. As more snow impacts the region in the next 18 hrs these storm slabs could become larger and more widespread. Any steep slopes with new snow on them hold the potential for storm slab avalanches. 

    Clues like cracking, collapsing, and whumphing can help identify where storm slabs may exist as can digging into the snowpack with your hands or probing with a pole to look for layers in the storm snow. Use these clues to avoid steep terrain where storm slabs may exist. Storm slabs can exist on tree covered slopes in the openings between trees and may connect across some of these open spaces. 

Avalanche Discussion

Yesterday observations on Tamarack Peak found ski kicks could easily trigger wind slab avalanches on exposed N-NE aspects with crowns of up to 2 ft. Shooting cracks caused by a skiers weight also occurred on wind loaded slopes. In more sheltered near and below treeline terrain on Tamarack Peak, Jakes Peak, and on Luther Pass, observations showed weaknesses within the recent storm snow, but fractures did not readily propagate along these weaknesses in many areas. Some skier triggered small cracking occurred on Tamarack and on Luther Pass in some sheltered areas. On Luther Pass, a ski cut on one test slope did produce a small storm slab failure. On Jakes Peak and in other areas on Tamarack and Luther Pass, ski cuts on test slopes only produced loose dry sluffs. Observations from lower elevation slopes (below 6400 ft) on Schallenberger Ridge did not find signs of slab formation or instability.

Regions covered