Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

You might still be able to trigger a large avalanche today above about 8,000' to 8,500'. The areas of greatest avalanche hazard exist near ridgetops, in gullies, and on open slopes where wind-drifted snow was deposited Thursday-Thursday night. Move cautiously around slopes that are below cornices or wind drifts.

Avalanche problems

  • Wind Slabs

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

    We received reports of two wind slab avalanches triggered yesterday by backcountry travelers. One avalanche was wide propagating with an approximately 3 foot crown. The other was confined to a steep chute and had a 6 inch crown. A few natural wind slab avalanches occurred Thursday night as well. While we are expecting less instability today than yesterday, triggering a large avalanche remains possible. 

    Rising snow levels during snowfall Thursday/Thursday night deposited increasingly denser snow on top of less dense snow. This created a slab over weak layer that is most pronounced in areas where wind drifted snow was deposited. Expect to encounter the greatest hazard near ridgetops, in gullies, and on open slopes where wind-drifted snow was deposited.

    Identify the slopes of concern, mainly those below cornice features or wind drifts. Move carefully around these areas, anticipating that an avalanche could be surprisingly wide.

    (12/27/2024) This wide propagating wind slab avalanche was unintentionally triggered yesterday by a snowmobiler. NE aspect terrain near 8,800' by Lost Lakes, CA, south of Carson Pass.

Avalanche Discussion

Rain crust exists on the snow surface across large portions of the forecast area. Depending on location, rain crust has been reported up to 8,600' to 9,200' in elevation. It may extend higher in some areas.

Over the past several days, incremental loading of deeper, faceted weak layers that linger above 8,000' to 8,500' in the eastern and southern portions of the forecast area has occurred. Thus far, these lingering weak layers appear to have handled the increasing load. That said, if you happen to trigger an isolated snowpack collapse or whumpf sound today, it's best to avoid NW-N-NE aspect avalanche terrain in the immediate area.

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