Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
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Pericolo valanghe

Alta quota
Senza grado
Limite del bosco
Senza grado
Sotto il limite
Senza grado
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In sintesi

Early season conditions update #6

Normal caution is advised throughout the forecast area with useable snow above 8000'.  The potential exists for minor loose wet snow avalanches at all elevations today with the forecasted rain and above freezing temperatures.   The ongoing deep slab avalanche problem in the Mt. Rose area continues to decrease, although some uncertainty continues for high elevation terrain.  Practice safe travel protocols when in or near avalanche terrain.

Problemi valanghivi

  • Cornices

    • Tutte le quote
    Probabilità
    Possible
    Dimensione
    0

    For areas in the forecast area along the Sierra Crest, a supportable snowpack of 2' deep exists above 8000'.  Above 8500', the snowpack increases to 3'+ deep.  In the Mt. Rose area, above 8500' also has a 3'+ snowpack.  Below 7200'-7800' throughout the forecast area, the snowpack is shallow with a minimal amount of useable snow.  Many hazards and obstacles exist throughout the region including: exposed trees, rocks, bushes, open water, creek crossings, etc.  Firm rain crusts exist in wind scoured terrain throughout the area and could pose travel hazards.  

    Above freezing air temperatures are expected through this week with the chance of light rain up to 10,000' today.  Surface wet snow may form on all aspects and elevations with the possibility of small roller balls depending on rain amounts received.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2

    The ongoing deep slab avalanche problem continues to be unlikely but not impossible.  This problem is specific to the Mt. Rose area above 8500' on NW-N-NE aspects.  This is a low probability but high consequence event.  Most recent observations have shown that the previous weak basal facets have been gaining strength, beginning to round, are moist, and have become non reactive to most snowpack tests.  Although an observation from Saturday at 10,000' on a NE aspect, had ECT results that showed propagation was likely on the loose basal faceted layer. 

    The deep slab avalanche problem has a higher level of uncertainty than other avalanche problems.  Our typical snowpack tests and informal observations are not as reliable with a deep slab avalanche problem as with other avalanche problems.  Conservative route finding and decision making along with standard bc travel protocols are best practice.    

Avalanche Discussion

-Several ECTP's on Mt. Houghton in the Mt. Rose area at 10,000' on the basal facet layer.

-SAC forecaster observations of the basal facet layer in the Mt. Rose area gaining strength.

-Graupel layer and near surface facets observed along the Sierra Crest at Carson Pass and the West Shore.

See specific observations below for more info.

Regioni coperte