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Out of date — this forecast expired 10 years ago.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

MODERATE avalanche danger will quickly form on slopes steeper than 35 degrees on E-SE-S-SW-W aspects at all elevations and may form on some sun-exposed near and below treeline NW-N-NE aspects as daytime warming makes loose wet avalanches possible again today. Evaluate snow and terrain carefully. Identify and avoid the areas where wet snow deep enough for loose wet avalanches exists.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Another day of warm temperatures, plentiful April sunshine, and light winds will quickly melt through the weak refreeze that may have occurred in some places last night. Once this refreeze melts, deep wet snow will exist on many slopes, and loose wet avalanches will become possible again today. While most of these loose wet avalanches should manifest as small point releases, roller balls, or pinwheels, some of the loose wet avalanches that occur today could entrain enough snow to cause problems for backcountry travelers especially in areas where the loose wet avalanches involve terrain traps. The size of loose wet snow instabilities will depend on the amount of recent snow that exists in a specific area. Expect to find deeper wet snow and larger more widespread wet snow issues in the Mt. Rose backcountry where the most snow fell during the recent storm. In areas along the Sierra Crest south of Highway 50 where less recent snow exists, most of the wet snow issues should remain smaller and entrain less snow. Wet snow instabilities in areas north of Highway 50 along the Sierra Crest and on the east side of Lake Tahoe south of Mt. Rose should fall somewhere between the other two zones. Slopes steeper than 35 degrees on sun-exposed E-SE-S-SW-W aspects at all elevations will hold the best potential for loose wet avalanches since they should experience the most warming, but some of the near and below treeline NW-N-NE aspects could also see enough sun for some wet snow instabilities to form. 

    Sinking into wet snow above your boot tops and small surface instabilities like roller balls, pinwheels, or point releases can provide clues that enough wet snow has formed for larger loose wet avalanches to become an issue. Moving to more frozen slopes or onto lower angle slopes off and away from slopes 35 degrees or steeper before deep wet snow exists on a slope represents a wise choice today. Terrain traps like gullies, creeks, and cliffs can greatly increase the risk of any size loose wet avalanches.

Avalanche Discussion

Yesterday 2-3 inches of wet corn snow existed on top of a supportable melt-freeze crust on the SW aspects of Castle Peak by 11 am. The SE-E aspects already held wet sticky snow on a barely supportable crust by that time, and small skier triggered loose wet instabilities had started to occur on steep previously-wind-loaded test slopes where more recent snow existed on the snow surface. Northerly aspects below 8000 ft. also held wet sticky snow on any sun-exposed slopes by 11 am in this area yesterday.  

Regions covered