Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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

Another day of warm temperatures and strong sunshine will form wet snow as daytime warming occurs.  Wet loose avalanches will become possible as the snow surface become deep and unsupportable due to a limited overnight refreeze.  Look for signs of wet unstable snow and move away from avalanche terrain if signs of instability exist.

Avalanche problems

  • Loose Wet

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

    Most all remote sensors above 7000' are reporting above freezing air temperatures overnight with stronger temperature inversions in place.  That leaves us with a superficial refreeze of the snow surface from radiational cooling due to clear skies overnight.  This snow surface refreeze will be less strong than what we have experienced during this recent corn cycle over the last several days.  Once this surface crust melts away and exposes deeper wet snow, wet loose avalanches will become possible.  Some wet loose avalanches could be large enough to cause problems for backcountry travelers, especially on long slopes where a wet loose avalanche could entrain more snow as it travels downhill.

    Monitor the snow surface as your travel in the backcountry.  As the surface becomes wet, deeper, and unsupportable-it's time to change aspects or move off of avalanche terrain.  Roller balls and pinwheels will be signs that the snow surface is losing strength and unstable wet snow conditions are present.  The window for supportable snow conditions will be shorter this morning than the last several days. 

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    The poor overnight refreeze may cause cornices to weaken more today with increased cornice fall potential.  These cornices exist along most ridgelines in the forecast areas and are large to massive in size.  These large blocks could fall downslope and could also trigger wet snow avalanches.

    Most cornice fall accidents occur during ridgetop travel and take the party involved by surprise. Stay well back from cornice edges, keeping exposed rocks or trees between you and the cornice edge. Consider avoiding travel on slopes below cornices.

    (4/15/2023)

    Recent cornice fall avalanche.  Round Top, Carson Pass area.

    Photo: SAC

Avalanche Discussion

  • Glide cracks have started to form on some steep slopes in rocky areas. Like cornice fall events, the exact timing of glide crack avalanches are notoriously difficult to predict. Due to the uncertainty, consider avoiding travel on or below slopes with glide cracks.
  • Over this weekend, the surface crust formed during overnight refreeze is expected to become thinner each night and melt faster each day due to increasingly warmer daytime and nighttime air temperatures. The window of time for travel in avalanche terrain before wet snow avalanche problems become a concern will get shorter each day. For travel in avalanche terrain, plan to start early and end early.

Regions covered