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

Areas of unstable snow continue to exist throughout the forecast region.  Human triggered avalanches will remain possible today at all elevations due to wind slab, deep slab, and loose wet avalanche problems.  MODERATE avalanche danger will exist.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Wind slabs could still be reactive in near and above treeline areas throughout the forecast area.  Periods of moderate SW to NE winds since the storm has ended could have built out wind slabs in wind exposed areas.  Large amounts of low density snow exists along ridges that can be easily wind transported.

    Look for blowing snow today or evidence of previous blowing snow.  New cornice formation or wind pillows may also be clues to where the wind has been transporting snow.  Slight changes in wind directions may build small wind slabs in unexpected locations.  Complex terrain may harbor these wind slabs on multiple aspects.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2

    Recent reports have come in that a deep slab avalanche cycle occurred on the buried facet/crust combination.  The majority of these reported avalanches are thought to have happened during the main loading event of the storm cycle on Sunday.  A human triggered deep slab avalanche was reported yesterday in the Ebbetts Pass area.  Details are very limited at this point.  Informal observations along with some snowpack test results have been trending towards this layer gaining strength, but more uncertainty now exists after this recent avalanche incident.

    This deep slab problem exists in near and below treeline areas on NW-N-NE aspects.  It is now buried anywhere from 3 to 6+ feet deep.  While these deep slab avalanches are becoming more unlikely, any avalanche associated with this layer would be large and destructive. 

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1

    Increasing solar radiation from strong March sunshine will make loose wet avalanches likely today.  Loose wet avalanches are expected to start mid to late morning as daytime warming and strong solar radiation warm the snow surface.  Roller balls and pinwheels may be an indication of larger loose wet avalanches becoming possible.  Many of these wet instabilities will occur around rocks, cliffs, and trees, as they heat up throughout the day.

    Avoid travel on solar aspects as the day begins to warm up in the mid to late morning.  Travel conditions will deteriorate as the snow surface becomes wet and sticky. 

Avalanche Discussion

A D2 deep slab avalanche was reported from Kinney Reservoir (Ebbetts Pass area) yesterday.  The avalanche occurred on a N aspect and failed on the old snow facets.  Limited details are available.

A natural avalanche was reported from the Fireplug in the Mt. Rose area.  This slab avalanche was around 1' deep on a N aspect.  There remains questions about this avalanche as it had wide propagation with shooting cracks off to the side and below the avalanche.  Some deeper instability or a potential deep slab may be associated with these avalanche characteristics.

Many reports of limited instabilities have been reported throughout the forecast region with greatly increased user traffic.  Snowpack tests targeting the deep slab problem continue to vary from location to location.

Regions covered