Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

You could still trigger a large and dangerous avalanche where new snow and wind have loaded weak layers buried beneath the surface. Recent avalanches, cracks, and collapses are signs that you should make careful terrain choices and maintain a wide safety margin. Factor the potential size and consequences of an unpredictable avalanche into your plans. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–3

    Very large natural avalanches failed on buried weak layers in the past 48 hours. Snow professionals remotely triggered a large avalanche on Wednesday, the first sunny day after a storm. Field observers in the northern half of the forecast area yesterday experienced collapses and shooting cracks near and below treeline. This matches reports from 9,500-11,000 feet across the forecast area of poor structure and similar signs of instability over the past week. The recent storm snow has made slabs thicker and potential avalanches larger. A smaller wind slab avalanche, or the weight of a person in a rocky area with shallower snow cover, could be all that’s needed to trigger an unsurvivable avalanche.

    Managing persistent slabs is difficult. They may be triggered remotely—from flatter terrain adjacent to steep slopes. Persistent slabs often propagate widely and in unpredictable ways. Shooting cracks and collapses are clear warning signs of the problem. However, feedback is often irregular. The best option is to minimize your exposure to steep terrain on the aspects and elevations with sugary facets buried under stiffer slabs. Use extra caution in rocky, complex terrain, near convexities, and on slopes with inconsistent snow depth.

    (2/7/2025)

    Large avalanches that stepped down to deeper layers. Liberty Chute area, Mt. Dana observed in the morning.

    Photo: Eastern Sierra Avalanche Center

  • Wind Slabs

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

    Recent snowfall and strong southwest winds over the past 48 hours have created wind slabs in exposed areas. Drifting continued, with new slabs forming throughout the day yesterday. Wind slabs can take hours or days to stabilize. With decreasing wind speeds, we expect sensitive slabs to slowly become more difficult to trigger. Exercise caution near ridgelines, in gullies, and on steep leeward slopes. Wind slabs may appear rounded and textured or sound hollow underfoot. Recent avalanches, shooting cracks, and collapsing in drifted snow are warning signs you’ve found unstable wind slabs. Wind slabs are stiff and dense, while softer, potentially safer riding can be found in wind-sheltered areas 

    (2/7/2025)

    Natural wind slab avalanche we watched fail on a road cut.

    Photo: Steve Mace

Avalanche Discussion

Notice the considerable overlap between the wind slab and persistent slab avalanche problems. Several avalanches we saw yesterday likely started as wind slabs and stepped down to deeper layers in the snowpack. 

Recent cracks, collapses, and snowpack tests have pointed to a thin layer of facets on top of the rain crust buried earlier this week. Layers of sugary facets and facet-crust combos are buried 1 to 3 feet deep at elevations without the crust–above about 9,500 feet–and deeper where thick wind slabs have formed on the surface. Slabs over weak snow are most common below alpine cliff bands, in sheltered areas, and on leeward slopes near treeline. Feedback from these persistent weak layers can be inconsistent and a dangerous source of uncertainty. Conservative terrain choice is the most surefire solution to the problem.

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