Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Unseasonably warm temperatures and sunny skies will keep the potential for Wet Loose avalanches top of mind. Monitor surface conditions closely today and retreat from steep slopes before surface snow becomes wet and unconsolidated.

Avalanche problems

  • Loose Wet

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

    Clear skies,  overnight temperatures near freezing, and continued winds led to a moderate refreeze overnight. As the sun comes out and temperatures rise, Wet Loose avalanche danger will rise quickly.  Lower elevation slopes and solar aspects will be the areas of greatest concern today.  Rollerballs or pinwheels and increasing boot penetration are signs of instability that often foreshadow larger point-release avalanches. Radiators such as cliffbands, rock features, and confined couloirs can trap heat and exacerbate the effects of warming. Wet Loose avalanches often fail from a single point and entrain heavy snow as they move downhill. The best way to manage Wet Loose avalanches is to avoid overhead hazard and be off of steep slopes before snow becomes too wet and unconsolidated.

    (2/23/2025) Photo: Samantha Rubin

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–3.5

    While targeted snowpack evaluations continue to show the potential for avalanches to propagate long distances, signs of instability, such as shooting cracks and collapsing in the snowpack, have become increasingly less common over the last week. Triggering a large slab avalanche has become unlikely. However, it is important to remember that while the likelihood has decreased, the size of a potential avalanche has not. A resulting avalanche will be large and destructive. Be wary of steep and complex terrain and areas with inconsistent snow coverage and shallow trigger points. This is particularly true in areas south of Mammoth and on slopes near and below treeline where buried weak layers are closer to the surface (~1 meter or less). Conservative terrain choice remains the best way to limit your exposure.

    (2/16/2025)

    Large Persistent Slab avalanche. Half Moon Pass -  Rock creek drainage

Avalanche Discussion

While unseasonably warm temperatures and sunny skies will keep our focus on the potential for wet snow instabilities today, the most notable change to the forecast is the decreased likelihood of a large persistent slab avalanche. Shifting this problem to unlikely is not a decision the forecast team takes lightly. It has been over a week since our last reported avalanche or sign of instability. However, targeted snowpack observations continue to highlight the potential for a large avalanche to propagate on weak snow deep in the snowpack.

So, what does this mean for you? This highlights a significant source of uncertainty. Initiating a failure on these buried weak layers will be difficult. It would likely require you to find a shallowly buried trigger point akin to finding the needle in the haystack. To put it another way, it would require some bad luck. However, if an avalanche fails, it will likely happen by surprise with no warning signs, and the consequences will be very high. Keep this in mind as you discuss field plans with your touring partners today. Low-probability and high-consequence situations are inherently difficult for us to manage. They can be fraught with false positives and high levels of uncertainty. When in doubt, remember that terrain choice is always your best tool in the toolbox to set yourself up for success. Choosing travel routes that avoid steep, complex terrain and overhead hazard will limit your exposure.

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