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, avalanche danger is LOW for all elevations and aspects. Areas of MODERATE avalanche danger are expected to form in response to daytime warming at all elevations on E-SE-S-SW-W aspects on slopes 35 degrees and steeper due to the possibility of loose wet avalanches. Isolated areas of loose wet instability may form on NW-N-NE aspects as well.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    A decent to strong snow surface refreeze is expected to have occurred last night with slightly colder overnight low air temperatures and decreased cloud cover as compared to 24 hours ago. That said, snow surface melt is expected to occur more rapidly today than yesterday due to decreased cloud cover, lighter winds, and slightly warmer maximum daytime air temperatures. Areas of unstable wet snow are expected to form by the late morning to mid day hours mainly on E-SE-S-SW-W aspects, especially below 8,000'. Instability will likely extend to the higher elevations as the afternoon progresses. Lesser amounts of snow surface melt are expected to occur on NW-N-NE aspects today. Subsequent loose wet instability will be less on NW-N-NE aspects, but may still occur in isolated areas.

    Use clues such as human triggered roller balls and pinwheels approaching or exceeding 1 foot in diameter and/or boot penetration 10 to 12 inches deep or more into wet snow to determine when critical amounts of surface wet snow exist. When these clues are present, move to lower angle slopes of less than 30 degrees in slope angle without steeper terrain above or change to a less sun exposed and more frozen aspect.

Avalanche Discussion

Observations made and received yesterday from Steven's Peak (Carson Pass area), Mt. Tallac (Desolation Wilderness area), and Castle Peak (Donner Summit area) all indicated that surface wet snow was slow to form yesterday above 8,500' to 9,000' due to the combination of cloud cover and moderate speed SW winds. Below 8,500', surface wet snow formation occurred relatively faster, but skier supportable conditions were reported on the SW aspects of Castle Peak during the late afternoon hours. Many SE-S-SW aspects and low to mid elevation E aspects have made the transition to "corn snow". Upper elevation E aspects and low to mid elevation NW-N-NE aspects remain transitional with a fairly thin layer of surface melt-freeze snow on top of drier older snow yet to under go melt-freeze. Upper elevation NW-N-NE aspects tend to hold fairly dense surface snow that has yet to undergo melt-freeze with the exception of low angle areas.

Regions covered