Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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

Wet loose snow avalanches will become possible today as last night's snow surface refreeze melts away, exposing residual deep wet snow below. Avalanche danger will start out LOW early this morning while the snow surface remains frozen, increasing to MODERATE danger as the frozen surface melts away and deep wet snow develops. Be advised that there is a slight chance of an isolated thunderstorm this afternoon.

Avalanche problems

  • Loose Wet

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

    Air temperatures were near to below freezing last night under mostly clear skies across the forecast area. A decent to strong overnight snow surface refreeze is expected to have occurred. This will have been driven by either the below freezing air temperatures or by radiational cooling in locations where air temperatures were above freezing. Keep in mind that only the very upper snowpack refreezes this time of year and that there is wet snow below the surface crust that did not refreeze last night.

    Once the surface crust is nearly or completely melted away, the wet snow on the surface will combine with the deeper residual wet snow below it. This will create potentially unstable conditions and allow for the possibility of wet loose snow avalanches. Once the surface crust starts to lose supportability, minimize risk by focusing travel on lower angle sub 30 to 35 degree slopes without steeper slopes above.

Avalanche Discussion

* Spring melt-freeze conditions are well established on most E-SE-S-SW-W aspects at all elevations. Superficial melt-freeze crusts and firm surfaces have been reported in the mornings. Observers have seen these crusts melt around mid-morning to mid-day leaving areas of deep wet slushy snow on these aspects for the afternoon.

* Large areas of bare ground have become exposed on many SE-S-SW aspects.

* NW-N-NE aspects are moving increasingly towards established spring melt-freeze conditions. Exceptions still remain where the upper snowpack is somewhere in between crust over winter-like snow and established spring melt-freeze conditions, especially at higher elevations and on steeper slopes that receive less direct sun exposure.

Regions covered