Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

Well above average temperatures and strong April sunshine will create unstable wet snow as daytime warming occurs.  A weak overnight snow surface refreeze is expected again for this morning.  Wet snow instabilities will become possible early as rapid warming occurs.  Move away from avalanche terrain as the snow becomes deep and unsupportable.

Avalanche problems

  • Loose Wet

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

    Well above average temperatures with light to moderate winds will continue for today.  Overnight temperatures were above freezing at most all sensors above 7000’, making any snow surface refreeze reliant on radiational cooling of the snowpack.  Increased cloud cover in some locations of the forecast area will limit this refreeze process.  Overall, a weak to marginal refreeze of the snow surface is expected for this morning.  Once this superficial refreeze melts away, unsupportable deep wet snow will be exposed with the potential for wet loose avalanche activity to occur. 

    The window for supportable snow and good travel conditions could be short again today.  Roller balls, pinwheels, and boot top wet snow will all be indicators that the snow surface refreeze has melted away and wet loose avalanches could occur.  As the snow surface becomes deep and unsupportable, it’s time to move away from avalanche terrain.

    Cornice collapses remain a concern in some areas.  In locations where large and overhung cornices exist along ridgelines, they will continue to melt, weaken, and potentially collapse. 

    (4/19/2024)

    Deep unsupportable snow on most aspects and elevations below 8800' at 11am.  Mt. Tallac.

    Photo: Sierra Avalanche Center

Avalanche Discussion

A size D2 wet slab avalanche was reported yesterday in the Donner Summit area.  While this avalanche is thought to be an isolated incident with wet slab avalanches unlikely today, they are by no means impossible.  As the snowpack continues to have marginal to no overnight refreezes, more wet snow instabilities could occur.  

The last avalanche forecast for the 2023-2024 season will post on April 21st. Thank you to all who contributed to the avalanche center this season through observations, volunteer time, and/or financial contributions.

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