Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

Sat
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Out of date — this forecast expired 4 years ago.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

Weak layers at the base of the snowpack mean you can trigger a large destructive avalanche today. Lookout for whumpfs, shooting cracks and other signs of unstable snow. Use conservative terrain choices to manage uncertainty surrounding the persistent slab problem.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    A persistent weak layer of faceted snow exists at the base of the snowpack throughout the forecast area. Observations from ski touring parties continue to highlight signs of instability. Reports of whumpfing and shooting cracks from yesterday are indications that a person's weight is enough to trigger the persistent slab. The areas of greatest concern are those in which the weak layer is within one meter (~ 3 feet) of the snow surface. The best strategies for managing persistent slabs are building a wide margin of error into your tour plan, and using conservative terrain choices to manage uncertainty.

    Persistent Slab avalanche in the June Lake area. 12/4/22

Avalanche Discussion

Variation in height of snow is an important factor in the nature of the persistent slab problem. In most of the forecast area, we still have a relatively shallow snowpack, which means that the persistent weak layer is less than ~ 1 meter from the snow surface and continues to give feedback with the classic signs of unstable snow such as whumpfs and shooting cracks. Around Mammoth Lakes where snow depth is between 4 and 6 ft. there have been fewer reports of signs of instability, but stability tests indicate that, if triggered, very large avalanches are possible.  Now is a good time to learn about avalanches by studying the snowpack.

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