Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 4 years ago.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

Highlights

Dangerous avalanche conditions exist. The most concerning areas are leeward slopes where dense drifts will be sensitive and large enough to bury you. In sheltered terrain, soft snow avalanches are likely. Use conservative terrain choices, with low slope angles, and avoid exposure to steep slopes overhead.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    Strong winds blew existing snow across the range over the past 24 hours. Renewed snowfall overnight has provided new material for building fresh slabs creating dangerous avalanche conditions. Expect drifts to be larger near and above treeline, though extreme winds can redistribute snow in unexpected ways. Don’t be surprised to find wind deposits in open areas below treeline and further down slopes than you may typically expect. Avoid areas of blowing snow and slopes that promote drifting. Steep terrain below ridges, gullies, and depressions are the most dangerous. Be aware of what's above you and plan to limit your exposure to overhead hazards.

    (1/6/2023)

    Large crowns from wind slab avalanches in steep gullies.

  • Storm Slabs

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

    Heavy snowfall rates of 2 inches per hour have been recorded this morning. New snow will not bond well to the old snow surface. Storm instabilities, both slabs, and sluffs, will be sensitive in steep wind-sheltered terrain. Convexities and confined terrain features deserve particular caution. Even small avalanches can be dangerous above terrain traps like cliffs or creek beds.

    (12/30/2022)

Avalanche Discussion

Extreme winds have been moving existing snow across the mountains for the past 24 hours. The hazard is rising now that new snowfall is providing a fresh round of ammo for the wind slab machine. The upper snowpack has been settling and stiffened by the wind. Hard wind board, crusts, and thin surface slabs were widespread in exposed terrain on Friday. Sheltered areas held unconsolidated snow and isolated pockets of surface hoar prior to the weekend storm. Fresh wind slabs and storm snow will take time to bond to these old surfaces. 

Deeper in the snowpack, rain crusts from late December storms exist up to about 9500 feet. Underneath, weak layers from late November and early December are buried 2 to 3 meters deep. These layers were wetted below treeline during the last rain event.  On a regional scale, persistent slab avalanches have become isolated and unlikely. A larger trigger such as a breaking cornice or a large wind slab avalanche may be required to initiate a failure in deeper weak layers. Intense new loading could bring the problem back to the forefront. Deep, very large natural avalanches may again become possible as the next atmospheric river moves into the region tonight.

Regions covered