Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
View on map

Avalanche danger

Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
Open full map
Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Stable snow is present in the vast majority of locations around the forecast area. The flip side is that very, very isolated areas of unstable snow may still exist. Use normal caution tactics to minimize the consequences of an unlikely and unexpected avalanche. Regional scale LOW avalanche danger exists at all elevations.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    Normal caution tactics are the name of the game today. The vast majority of locations out there today will look stable and act stable. The concern is for the potential outlier of a very, very isolated NW-N-NE aspect below treeline or near treeline that still holds some lingering instability. The weak layer would be the remnants of the Nov 13 facet layer located a few inches above ground level.

    An avalanche today would come as a surprise for those involved. Use the normal caution tactics of making a plan, carrying companion rescue gear, using effective communication to ensure that all party members understand the plan and the hazard. Expose only one person at a time to avalanche terrain, do not rely on marginal safe zones, and do not underestimate the avalanche size potential on a small slope. These are the tactics to minimize the consequences of an unexpected avalanche.

    Increasing SW winds today are not expected to cause much in the way of blowing and drifting snow that would deposit in lee areas as problematic new wind slab development. If you do encounter areas of visibly drifting snow, take a minute to pause and evaluate. Ridgeline locations near existing cornice overhangs hold the greatest potential for drifting snow. Slopes below cornices are easy to avoid with only minor route changes.

     

Avalanche Discussion

The snowpack tends to be supportable but remains thin with numerous obstacles to hit. The best coverage exists above 7,300' to 7,800’ along the Sierra Crest and above 8,600’ in the Mt. Rose area.

We have been tracking strength gains on the previously problematic Nov 13 weak layer of facets near the bottom of the snowpack. Stabilization does not occur at the same rate in all locations. However, in the vast majority of locations around the forecast area, snowpit data has indicated that this layer has bonded well to the snow above and below it in recent days with no further indications of instability. The only known outlier are unstable snowpit tests on this weak layer that occurred Friday above "The Grills" just west of Mt. Lola (Independence Lake area) in northerly aspect below treeline to near treeline terrain around +/-8,000'. Snowpit data collected yesterday about 5 miles to the east of this area on a below treeline NE aspect at about 8,400' gave no indications of instability on the Nov 13 facet layer. Any lingering instability is very isolated. No avalanches have been reported failing on this layer since the peak of instability back on Wednesday (Nov 18).

Regions covered