Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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

Last night's refreeze will be short lived this morning. Once the surface crust melts away, a loose wet avalanche problem will be present. Cornice fall remains an additional hazard. MODERATE avalanche danger exists today at all elevations. The last avalanche forecast for this season will post on May 3rd.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Air temperatures were even warmer and further above freezing last night than the night before. A weak snow surface refreeze driven from radiational cooling of the snowpack is expected to have occurred once again under mostly clear skies. The relatively thin and superficial melt-freeze surface crust formed overnight will melt rapidly today. The widow of supportable snow surface conditions will be short lived this morning. Once the surface crust melts away, residual deep wet snow below it will be exposed. This exposed deep wet snow will be prone to loose wet avalanches on all aspects and at all elevations. Avalanche size is expected at D1 to D2, depending on what the terrain is capable of producing.

    Avalanche problems will develop quickest on E-SE-S aspects, with the other aspects not far behind today. This avalanche problem can be avoided by choosing not to travel in or below avalanche terrain once the surface crust has melted to the point that it is no longer supportable. Use aspect and slope angle to your advantage. Winds may briefly slow melt rates near ridgetops this morning, but expect rapid warming on the slopes below.

  • Glide Cracks

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Cornices that exist along many ridgelines will continue to collapse today. Large falling blocks of snow could injure a person on their own and may entrain more wet snow or trigger a loose wet avalanche when they impact the slope below.

    Cornices frequently break farther back from their edge than expected. Cornices can also fail at unexpected times. Stay far back from the edges of cornices while on ridgetops and avoid travel underneath cornices.

Avalanche Discussion

* Spring melt-freeze conditions exist on all aspects across the forecast area. Meltwater drainage from the snowpack appears well established in many areas.

* Observations made yesterday on Incline Peak (Mount Rose area) and Pyramid Peak (Desolation Wilderness area) reported a weak to decent snow surface refreeze from the night before. The surface crust formed from this overnight refreeze melted away very quickly yesterday morning on all aspects.

* Large chunks of cornice fall continue to occur from the locations where large cornices exist.

* Numerous glide cracks exist were the snowpack overlies steep slabs of rock. No signs of glide avalanches have been observed.

Regions covered