Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

 Triggering an avalanche is more likely in places where a stiff and cohesive slab rests over weak sugary snow. Areas with more significant coverage will also be areas with heightened avalanche concerns. Keep in mind that any avalanche involvement today will come with elevated consequences due to the very shallow and rocky nature of our snowpack.

Avalanche problems

  • Persistent Slabs

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

    While weak faceted snow dominates the forecast area, slopes where winds have added weight and cohesion to the overlying slab are of greatest concern. On a regional scale, these slopes are isolated in nature. However, they are also areas with more substantial coverage. This means that areas with enough snow to be attractive to backcountry travelers are the same areas that may contain the setup for an avalanche. Signs of instability include recent avalanche activity, shooting cracks, whumping, and collapsing in the snowpack. It may be possible to trigger a persistent slab avalanche from adjacent slopes, and avalanches may propagate long distances. Remember that being carried in an avalanche today will have elevated consequences due to our snowpack's very shallow and rocky nature. The easiest way to avoid this problem is to stick to lower-angle terrain without overhead hazards.

    (12/24/2023)

    This avalanche failed on buried facets and likely ran on 12/21

    Photo: Clancy Nelson

Avalanche Discussion

A few important points stand out to me as we patiently wait for winter to take hold in earnest here in the Sierra.

Coverage is thin. On a regional scale, continuous snow coverage is largely confined to upper elevations and areas closer to the Sierra crest. The exception to this is centered around the Mammoth area where some continuous coverage exists below treeline. If you venture out into the backcountry, be ready to contend with terrain riddled with rocks, fallen trees, exposed bushes, and open water.

We have a very weak snowpack structure. Field observations continue to highlight well established basal facets and large depth hoar in most locations near and above treeline. While loose sugary facets can be found in most locations, our avalanche problems are isolated for the time being, confined to areas where the winds have helped build the slab. This will likely change when we see more substantial precipitation. In the meantime, it is important to remember that we are in a tricky situation where travel options are extremely limited and areas with “enough” snow to travel are the same areas where an avalanche is more likely to occur.

 

Regions covered