Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

Today's wind, light rain, and snow aren't expected to do much to change avalanche conditions. Triggering a large avalanche in an isolated area has become unlikely, but is certainly not impossible due to the current snowpack structure. Best practice backcountry travel techniques associated with normal caution are advised.

Avalanche problems

  • Persistent Slabs

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

    Some observation data continues to indicate the possibility of triggering an isolated, large avalanche, but it is becoming increasingly unlikely.

    If you happen to trigger a snowpack collapse, whumpfing, or a large avalanche, you found an isolated area of instability, and it's worth pulling back from any NW-N-NE aspect avalanche terrain in the vicinity. Any isolated areas of unstable snow capable of producing a large avalanche are going to be in areas where a shallower snowpack exists, such as the northeastern, eastern, and southern portions of the forecast area.

    Most people will not see signs of unstable snow today. That makes triggering one of these avalanches an unexpected event for most groups. Since one of these avalanches will probably be surprisingly large, choosing simpler terrain and exercising wide safety margins may help reduce the consequences in avalanche terrain. Non-avalanche terrain options on NW-N-NE aspect slopes or choosing alternative aspects are the best bet if you simply wish to avoid this low likelihood-high consequence problem.

    Depending on the size of additional storms over the next week, our persistent weak layers of concern could become more reactive.

    (12/18/2024)

    Pointing at the lingering persistent weak layers of concern, Dec 12 facets and basal facets/depth hoar. All the snow above the right hand was accumulated during the last storm cycle. N aspect, 8,960', Price Peak NV

    Photo: Sierra Avalanche Center

Avalanche Discussion

On a regional scale, little to no snow exists for wind transport this morning due to rain crust on the snow surface up to 8,300' and melt-freeze crust on windward aspects up to 9,000'+. There might be a small amount of snow available for drifting this morning at the highest elevations. Once snowfall begins, there is a small chance for some thin slabs of wind drifted snow to form this afternoon and evening above about 7,500'. This would only occur if the high end of forecast snowfall (3 to 4 inches) were to accumulate. Light rain on snow below about 7,500' today is not expected to cause any wet snow instability due to preexisting rain crust on the snow surface.

Regions covered