Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

Fri
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Out of date — this forecast expired 2 years ago.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

As surface snow melts, wet loose avalanches will become possible on steep, sunny slopes that have snow cover. Old wind deposits could surprise you where they sit atop weak, sugary snow below ridgelines and in gullies. Lower-angled, shady, and sheltered slopes have softer snow and are the safest alternative to both avalanche problems.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Today will be the warmest day of the week. The freezing level rises above 11,000 feet, winds decrease, and it will be gloriously sunny. These factors will combine to thaw the recent low-density snow on solar aspects. Sunny slopes with snow cover are limited, especially south of Mammoth. There is less coverage and less snow to melt at lower elevations, where wet avalanches should be smaller. 

    The best way to manage Wet Loose avalanches is to travel when the snow surface is colder and stronger. Time your trip to avoid crossing on or under very steep slopes in the heat of the day. Move to colder, shadier aspects before the snow surface turns slushy. Rollerballs and pinwheels are obvious warning signs for Wet Loose avalanches.

    Photo: Steve Mace

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Shifting winds during last weekend’s storm hammered upper elevations and hit near treeline in areas closer to the Sierra Crest (like Mammoth and June). On northerly aspects, old slabs may still be sensitive where they rest atop a layer of weak, sugary facets. These may be less predictable and harder to manage.

    Wind slabs typically form below the leeward side of ridges or in crossloaded gullies. Cracking or collapsing in drifted snow are clear warning signs of the problem. Softer, safer riding can be found in wind-sheltered areas.

    (12/24/2024)

    Shooting crack in wind stiffened snow

    Photo: Steve Mace

Avalanche Discussion

Avalanche Activity: Small slab avalanches and loose snow sluffs were observed in the Mammoth and June areas around the 26th, mostly occurring during or immediately after the storm. A snowpack test on the 27th near Red Cone indicated propagation under a thick wind slab over facets, though these larger slabs seem to be outliers. On Tuesday and Wednesday, observers reported localized cracking and collapsing on facet layers beneath cohesive wind slabs. Snow that accumulated in northerly start zones was stripped by shifting winds, and slabs on sunny aspects have likely stabilized after exposure to warm sunshine.

Snowpack Summary: Before the storm on the 25th, wind-exposed and sunny slopes had firm crusts or bare ground. Protected, shady terrain had a layer of well-developed surface facets. The storm brought 2 to 18 inches of cold snow, which was redistributed by variable winds, especially at higher elevations. The recent snow is still loose and has been faceting, with snow surfaces melting on solar slopes during the sunniest parts of the day.

Regions covered