Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
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Pericolo valanghe

Fri
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Slabs of wind blown snow could continue to be unstable today.  Rapid warming with strong sunshine will form wet snow on sun exposed slopes.  Wet loose avalanches will become possible as daytime warming occurs.  Make a plan that addresses these changing conditions throughout the day. 

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Solar radiation from strong March sunshine and warming temperatures will develop a wet loose avalanche problem today.  Wet loose avalanches are possible on sun exposed slopes as daytime warming occurs.  Roller balls and pinwheels along with larger wet loose avalanches that entrain sizeable amounts of snow will become possible.  Sun exposed slopes will become increasingly unstable as daytime warming occurs today with full sunshine.

    Even small wet loose avalanches can have consequences, especially if you are above a terrain trap (rocks, trees, cliffs, gullies, etc).  Larger slopes will have the potential for bigger and longer running wet loose avalanches.  As the snow surface becomes wet, it's time to change aspects or move off of avalanche terrain. 

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Lingering wind slabs on NW-N-NE-E-SE aspects continue to pose concerns for today.  A density change in the previous storm snow with high elevation rain/heavy wet snow has created a more dense layer over weaker snow.  Snowpack test results in some areas show continued weakness on this layer.  Rapid warming and intense solar radiation may further weaken these bonds where these wind slabs exist on sun exposed slopes.  To a lesser extent, winds have shifted to the NE overnight into the moderate to strong range.  They are forecasted to decrease back to the light range later this morning.  Limited snow exists for wind transport, but small amounts of snow may have been blown to SE-S-SW-W-NW aspects forming additional small wind slabs.

    Look for blowing snow and snow surface clues to see where wind transport has been occurring.  Cracking in the surface snow could indicate the presence of wind slab.  Give a wide safety margin to large cornices that exist along most ridgelines throughout the forecast area.   

    (3/15/2023)

    ECTP on  wind slab.  Carson Pass area.

    Photo: SAC

Avalanche Discussion

  • Another large avalanche cycle occurred on Tuesday March 14 during a wet and warm AR storm.  Widespread wind and wet slab avalanches have been reported with large cornice collapses throughout the forecast region.  See the media gallery below or our observation page for more details.
  • Rain on Tuesday March 14 went up to 9000' and potentially higher in some areas.
  • A cornice collapse shed cycle started to occur on Tuesday March 14 during a warm and wet AR storm with high elevation rain.  Large cornices continue to exist throughout the forecast region and could weaken and collapse over the next couple days with intense solar radiation and warmer temperatures.  With the current weather conditions, cornice collapses are not expected to be as widespread as what was seen on Tuesday.

Regioni coperte