Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
Out of date — this forecast expired 10 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Daytime warming will create enough wet snow on sun-exposed E-SE-S-SW-W aspects for MODERATE avalanche danger to develop on slopes steeper than 35 degrees at all elevations. Loose wet snow avalanches including roller balls, pinwheels, and point releases will be possible today. Most of these loose wet snow instabilities should remain small, but some of them could entrain enough snow to pose a threat to backcountry travelers especially those that occur around terrain traps.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Last night's clear skies will have allowed the snowpack to lose enough heat for some overnight refreezing even though temperatures remained above freezing in many areas. The strong March sun and warm daytime temperatures will quickly melt through this refreeze in most areas, and deep unsupportable wet snow will form on many slopes today. The forecasted cloud cover and slightly increased winds do have the potential to slow down the melting process if they materialize. After going through several days of melt freeze cycles the snowpack has transitioned to more corn snow conditions in some areas and not in others. Once the refreeze melts, loose wet snow avalanches in the form of roller balls, pinwheels, and point releases will become possible again today especially on slopes where the wet snow exists on top of drier colder snow with less well established drainage channels. The sun exposed E-SE-S-SW-W aspects hold the best potential for loose wet avalanches. Most of the loose wet snow instabilities should remain small, but some of them could still entrain enough snow to cause problems for backcountry travelers.

    Use clues like sinking into boot-top deep wet snow and smaller surface wet snow instabilities like roller balls and pinwheels to indicate that enough wet snow exists for problematic loose wet avalanches. These signs indicate that the time has come to move to more frozen slopes, move to less steep slopes, and/or switch activities for the afternoon. 

Avalanche Discussion

Knee deep unsupportable wet snow had formed by noon on sun-exposed southerly aspects on Rose Knob Peak in the Mt. Rose backcountry below 8200 ft. yesterday. Above this elevation a few inches of wet snow existed above a supportable melt-freeze crust until that time. Farther south on Carson Pass daytime warming had allowed enough wet snow to form for some roller ball activity all the way up to 10,000 ft. on Round Top. Northerly aspects still held a mix of firm but cold wind packed snow and crusts above 8000 ft. in the Carson Pass area. In both the Rose Knob Peak area and the Round Top area several recent cornice failures had occurred and large cracks had formed behind many cornices that did not fail. 

Regions covered