Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

MODERATE avalanche danger will exist this morning with wind slab avalanches possible in near and above treeline areas.  Avalanche danger will increase quickly this afternoon to CONSIDERABLE as another storm impacts our area.  Wind slab avalanches will become likely this afternoon in near and above treeline areas, with storm slabs growing in size through the evening and into Wednesday.  Dangerous avalanche conditions will develop as this storm starts to intensify today. 

Avalanche problems

  • Wind Slabs

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

    A first round of wind slabs have been created overnight with additional new snow and continued strong to gale force SW winds.  These SW winds will continue through today adding to the existing wind slabs on NW-N-NE-E-SE aspects in near and above treeline areas.  As another storm impacts our area this afternoon bringing more snow with continued SW winds, wind slabs will continue to build in size.  Wind slab avalanches are expected to be possible this morning and will increase to likely this afternoon as storm intensity increases.

    Look for blowing snow, new cornice development, and newly forming wind pillows.  The low density snow should be easily wind transported in near and above treeline areas.  Use caution around newly formed cornices below ridges and steep wind loaded slopes.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    Storm slabs will be unlikely for most of today due to the limited amounts of new snow.  As the storm starts this afternoon and continues overnight, total snowfall will reach levels where storm slab avalanches will become possible.  Storm snow instabilities could occur within the new storm snow or at the new snow old snow interface.  In isolated areas, the new storm snow may have difficulty bonding to the old snow surface or just below where near crust  facets may exist.  If signs of instabilities are encountered, pull back into below 30 degree terrain with no overhead hazards.  

Avalanche Discussion

* Snowpit observations have noted that faceting has started to weaken the snowpack around the buried Feb 19 rain crust in the upper portion of the snowpack on some NW-N-NE aspects. New loading of this developing weak layer remains minimal at this time.

* Cloudy and windy conditions were reported across the forecast area yesterday.  Some areas received very light snowfall throughout the day.  

Regions covered