Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
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Pericolo valanghe

Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 12 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Avalanche danger is LOW for all elevations and aspects. Normal caution is advised.

 

Problemi valanghivi

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1

    Isolated persistent slab avalanches are a very low likelihood problem at this time. A difficult to trigger weak layer of basal facets lingers above 9,000'-9,500' on NW-N-NE aspects. The most likely points for human triggering exist at relative shallow areas of the snowpack commonly found near exposed rocks, isolated trees, and along cliff bands. Exercise normal caution and manage terrain to avoid potential trigger points.

    The bigger picture issue is how these facets will react to the expected new snow loading Thurs/Fri. If the current forecast of several feet of new snow above 8,000' verifies, large and potentially destructive deep persistent slab avalanches could very well become a concern. It is still a bit early to commit to this line of thinking, but file it away and start brainstorming appropriate terrain and snowpack management techniques for deep persistent slabs. As seen in yesterday's observations, slopes that received heavy traffic after the last storm will not be immune. After brainstorming for a bit, check here for accuracy of ideas and further guidance.

Avalanche Discussion

Observations made yesterday on Incline Lake Peak (Mount Rose area) showed that the basal facets that exist on NW-N-NE aspects above 9,000'-9,500' remain problematic. Despite some evidence of rounding, these facets remain loose grain and weak. Snowpit tests performed on a N aspect, ski track covered slope at 9,500' showed that the weak layer and overlying slab retain the necessary characteristics for sudden collapse and propagation of fracture over distance. This is despite all of the traffic that the snowpack in this area has received. (video)

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