Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

Wed
Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
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Highlights

Increasing winds and modest amounts of loose surface snow could create small wind slabs today on leeward terrain features near and above treeline.  It may also be possible to trigger a small avalanche in areas where a stiff slab rests over a weak layer of loose, sugary snow near the ground. Thin coverage will increase the consequences of any avalanche involvement today. Hazard will increase quickly overnight if predicted snow totals verify.

Avalanche problems

  • Persistent Slabs

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

    Weak and unconsolidated snow dominates in areas that have continuous coverage. In isolated areas, a slab of stiff and cohesive snow overlays these weak facets. Problem areas are most likely found on terrain features prone to wind-loading, especially in the Mammoth Area and near the Sierra Crest.  If triggered, a resulting avalanche could break with little warning, involving the full depth of the snowpack. Managing this problem may be more difficult because poor snow coverage means that the few areas attractive for riding are generally the same slopes where the avalanche problem may exist. If the current weather forecast verifies persistent slabs will grow in size and become more sensitive as the current snowpack receives its first real stress of the season.

    (12/24/2023) Photo: Clancy Nelson

  • Wind Slabs

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

    Strong winds returned to the region overnight. While loose surface snow is limited, it will not be impossible for thin and small windslabs to form in leeward catchment zones near and above treeline. You can expect the size and distribution of fresh wind slabs to grow quickly as fresh snow begins to accumulate this evening.   While a resulting avalanche today will likely be small, these slabs could be a concern in steep or exposed terrain where a short ride or a tumbling fall may have serious consequences. Recent drifting, hollow upside-down feeling snow, and uneven snow surfaces are all clues that indicate nearby wind deposits. Do your own localized assessments and be suspect of terrain features that encourage drifting, such as the leeward sides of ridgelines, alpine couloirs, gully features, and cross-loaded depressions.

    (1/6/2023) Photo: Cracking in wind slabs

Avalanche Discussion

It's felt a bit like Groundhog Day here in the eastern Sierra with our slow start to the winter season. While things are expected to remain relatively quiet during the day today, this may begin to change tonight. While some fresh snow is precisely what we have been waiting for, it will be crucial to keep in mind that this will be the first load to test our weak snowpack structure. If the weather forecast verifies, we could see up to an inch of water weight near the crest and enough snow to double our coverage in some areas.

This is not the typical Sierra “crush and flush” scenario where natural activity dominates during the loading event, and multiple feet of snow change the situation overnight. Instead, this incremental loading could lead to a spooky situation for backcountry enthusiasts where human-triggered avalanches become more likely over time. On the heels of a record snow year, this meager start to the winter season is already testing our patience. This patience will continue to be imperative as we move into a period of more active weather and increasing avalanche hazard.

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