Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Avalanches of unstable wind-blown snow remain possible today. The strong sunshine may also allow wet snow to slide down slopes or make it easier to trigger slab avalanches. Watch out for places where wind-blown snow has piled up near ridges or in gullies and sunny slopes with new snow on them.

Avalanche problems

  • Loose Wet

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

    The strong April sunshine could provide enough warmth to weaken the new snow even though temperatures should remain near or below freezing in most places today. Some wet snow instabilities like roller balls, pinwheels, or even a wet loose avalanche may be possible today on steep sunny slopes. In areas where the new snow remains more cohesive, triggering a soft slab avalanche may not be impossible as the new snow warms up. E-SE-S-SW-W aspects will experience the most direct sunshine and will also hold the best chance for these "sun on new snow" instabilities.   

    Pay attention to the snow conditions as you travel. The sun could cause the snow to warm up quickly. Once the new snow starts to feel warm or you see any signs of wet snow like rollerballs or pinwheels, it is time to move to an area where the snow remains cold or move onto lower angle slopes without avalanche terrain above them. 

  • Wind Slabs

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

    Yesterday's wind piled snow onto the leeward side of ridges and gullies. These wind slabs rest on top of icy crusts and have several weaknesses within the wind-loaded snow. Wind slab avalanches will remain possible today. Wind slab avalanches that occur today could involve enough snow to bury or injure a person. The largest wind slabs will exist in near and above treeline terrain on NW-N-NE-E-SE aspects. The strong April sun could further weaken the wind slabs and make it easier to trigger a wind slab avalanche on a sunny slope.

    Clues that can help determine where wind slabs exist include new cornices above a slope, scoured areas along a ridge, ripples on the snow surface, and drifts of wind-blown snow. Identify where unstable wind slabs may remain and move cautiously around those areas. Traveling in wind-sheltered areas can help avoid potential wind slab issues and may provide softer, more consistent snow conditions.

    (4/11/2022)

    Wind loaded test slopes along Frog Lake Ridge near Carson Pass failed both very close to the surface and several inches deep. Two ECTs propagated on a third weak layer just above the new/old interface.

    Photo: Travis Feist

Avalanche Discussion

  • Many NW-N-NE-E aspects still had decent snow coverage prior to yesterday's storm. Large areas of bare ground or very limited snow cover existed on most SE-S-SW-W aspects.
  • Yesterday's new snow barely covered a variety of obstacles and hazards including exposed rocks, dirt, bushes, down trees, branches, open water, firm crusts, and running creeks.

Regions covered