Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

Fri
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

Very dangerous avalanche conditions exist today. Large natural and human-triggered avalanches are likely at all elevations. Travel in or beneath avalanche terrain is not recommended. 

Avalanche problems

  • Wind Slabs

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

    Significant snowfall over the last 12 hours was accompanied by strong to extreme winds out of the south-southwest. Winds are expected to remain at transportable speeds with continued showers throughout the day. You can expect recent deposits near and above treeline to be large as you walk out the door this morning and continue to grow in size and sensitivity throughout the day. Blowing snow and growing cornices will point to the most dangerous slopes. Stiff, textured drifts could fail naturally and break widely under ridgelines and on the sidewalls of gullies. Poor visibility will make it hard to assess the terrain above you.  Avoid being on or near steep wind-loaded terrain and in the runouts of avalanche paths. 

    (12/28/2022)

    Crown line and bed surface of size 2 human-triggered wind slab in Redcone Bowl

  • Storm Slabs

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

    Last night’s storm brought up to 2 feet of new snow to favored areas and rates as high as 3” per hour. While we expect snowfall to taper off significantly today, continued showers could bring periods of heavy snow with rates over 1” per hour locally along the Sierra crest. Surface instabilities, both slabs and sluffs, will be most sensitive early this morning in steep and sheltered terrain near and below treeline. Convex rollovers and steep, unsupported slopes are areas to avoid today.  It is also important to be aware of potential terrain traps that can increase the consequences of an avalanche. Road cuts, gully features, cliff bands, and mid-slope depressions are all places that can increase the consequences of an avalanche.

    Photo: Steve Mace

    2/14/2025

    Storm Slab avalanche in the mammoth area

  • Persistent Slabs

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

    A substantial load has been added to our snowpack over the last 12 hrs - over 2” of water weight in the Mammoth area and close to 1” in the Bishop area. It has been a while since we last saw avalanches breaking on weak layers buried deeply in the snowpack. However, forecasters have continued to find poor structure and propagating test results on persistent grains 3+ feet below the surface. Snowpacks do not like rapid change, and our recent load may be enough to stress this poor structure. While less likely than surface instabilities today, the consequences of an avalanche breaking deep in the old snow will be very high.

    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 large 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, particularly in rocky, complex terrain, near convexities, and on slopes with inconsistent snow depth.

Avalanche Discussion

While new snow will undoubtedly be a powerful draw for the backcountry enthusiast, today is a day to move with extreme caution and to give yourself a wide margin for safety. Better yet, avoid avalanche terrain altogether. Large avalanches, both natural and human triggered, are likely today. Overlapping problems on a complex snowpack, continued loading, and high variability in recent snow totals will make for difficult and high-stakes decision-making.

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