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

Early this morning LOW avalanche danger exists for all elevations and aspects. Starting during the mid to late morning hours and progressing through the rest of the day, MODERATE avalanche danger will form on all aspects and elevations on slopes 35 degrees and steeper due to potential wet snow avalanches. It is best to avoid travel in avalanche terrain during the afternoon hours.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    A decent to strong snow surface refreeze is expected to have occurred last night. Air temperatures were at or a few degrees above freezing overnight rather than in the upper 30s and 40s. Clear skies will have allowed for significant radiational cooling. Conditions for snow surface refreeze were much better last night than the previous two nights. As daytime warming progresses, snow surface melt will occur on all aspects. The high sun angle of April will rapidly melt E-SE-S-SW-W aspects this morning and cause a slower rate of melt to occur on upper elevation NW-N-NE aspects.

    A window of supportable snow surface conditions with a couple of inches of wet snow on the surface will exist this morning. Once the melt-freeze crust that formed last night melts away, deeper and weaker wet snow that did not refreeze last night will be exposed. Once the snowpack looses supportability to a person on foot, it is time to exit avalanche terrain. Waiting until skis, boards, and sleds penetrate deeply into wet snow is well into the window of snowpack instability for loose wet avalanches.

Avalanche Discussion

Observations made yesterday on Tamarack Peak (Mount Rose area) and on Red Lake Peak (Carson Pass area) confirmed that a poor snow surface refreeze had occurred Sunday night. In both locations, the poor snow surface refreeze was readily apparent at the trailhead during the mid morning hours. On Tamarack Peak, the crust that did form was only about 1.5 inches thick and did not support the weight of a person on foot in many open areas at 9:30 am. It was also confirmed that an isolated wet slab avalanche had occurred on the Diamond slope of the Fireplug feature near Tamarack Peak on Sunday at 12:30 pm. For more details on the wet slab avalanche see below.

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