Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

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

Dangerous avalanche conditions exist. Fresh and sizable wind deposits are of greatest concern; however, storm instabilities remain possible in more sheltered areas near and below treeline.  Keep overhead hazard top of mind today and be aware of terrain features that increase the consequence of avalanches.

 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1.5–3

    Winds are expected to continue at strong to extreme speeds today. You can expect continued slab development throughout the day and resulting wind slabs are likely to be large and reactive. While most concerning near and above treeline, Strong winds can redistribute snow in unexpected ways. Don’t be surprised to find reactive wind deposits in relatively sheltered areas below treeline and further down slopes than you may typically expect to find them. Be suspect of terrain features that encourage drifting such as the leeward sides of ridgelines, gully features, and cross-loaded depressions.  Large to very large natural and human-triggered avalanches are likely today. Avalanches may run long distances and into lower angle, or treed terrain you may typically think of as “safe”.

    Large Natural avalanche - NE 10200', June Lake backcountry 202301017

  • Storm Slabs

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

    Snowfall rates during the last 48 hrs hit periods of well over 2” an hour and storm totals over 70” have been recorded throughout the range. This recent storm snow is expected to gain strength relatively quickly today, however, avalanches breaking within the new snow are likely to be large in size. Approach steep terrain over 30° today with caution and be cognizant of your exposure to terrain features that increase the consequences of avalanches. This includes road cuts, gully features, cliff bands, and mid-slope depressions.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    3–3.5

    The weight of a skier or rider is not likely to be enough today. A larger trigger such as a wind slab avalanche or large cornice break will be necessary to trigger a deep slab avalanche. While unlikely, an avalanche breaking near the ground has the potential to be very large and destructive. Steep and unsupported slopes, large avalanche paths, and areas with shallow trigger points, are areas to consider. Uncertainty around deep slab instabilities is very high and managing this problem requires extensive evaluation and deliberate terrain choice. Deep slab avalanches often fail without warning, they can propagate across and beyond terrain features that would otherwise confine surface instabilities such as wind or storm slabs, and in some cases avalanches can be remotely triggered from adjacent slopes. Give yourself a wide safety margin, be wary of hazards that may reside above you, and use terrain choice to limit your exposure.

    (1/7/2023)

    Crown line of a Natural D3 avalanche on a NE aspect at 11000' 20230107

Avalanche Discussion

As this most recent storm begins to exit the region today it will be important to take stock. Make no mistake over the past 72 hrs we have seen an extreme weather event. Very heavy snowfall rates and large accumulations largely shut down mountain communities and heavy rain led to flooding in the bishop area.  At the time of writing this, evacuation orders remain in effect for communities in June lake and Long Valley, and reports have come in about a large avalanche damaging several unoccupied homes in the Aspendell area. Emergency services and road crews are working hard to open roads and provide access to mountain communities however it will be important to remain patient. Be selective about when and where you choose to travel and be thoughtful of how you park at trailheads, in town, and along roadways. Parking in front of snowbanks or in non-designated areas prevents road crews from being able to clear the roads. 

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