Bollettino valanghe

Eastside Region

Eastern Sierra Avalanche Center
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Pericolo valanghe

Sat
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

On a regional scale avalanche activity has become unlikely. Dense and stubborn wind slabs may still be possible to find in leeward catchment zones and in extreme terrain. Extra consideration is recommended in steep open bowl features, mid-slope depressions and in areas where terrain features elevate the consequences of an avalanche.

Problemi valanghivi

  • Wind Slabs

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

    Recent field observations have highlighted widespread impacts from our recent extreme wind event. While supportable wind board is widespread and present at all elevations, areas with concerning windslab development are more isolated in nature.  It will not be impossible to trigger an avalanche today. Particularly on northerly and easterly terrain features and areas where older, dense, wind deposits are resting on weak underlying snow. Recent avalanche observations suggest the most likely areas to find these hard slabs are mid-slope depressions further down from ridgelines than you may typically expect, and in catchment zones near treeline. Hard wind slabs may feel strong under a rider's weight but they can fail suddenly and unexpectedly.  They can initiate above you, accelerating quickly, and traveling long distances down slope. Triggering hard slabs is often most likely near the edges where slabs are thinner or by finding a shallow trigger point near rock outcroppings or cliff bands. Watch for clues like textured snow surfaces, large fresh drifts, and hollow upside-down feeling snow. Be suspect of terrain features that have encouraged recent drifting, such as the leeward sides of ridgelines, alpine couloirs, mid-slope convex rollovers, and cross-loaded depressions.

Avalanche Discussion

Recent avalanche considerations have been tricky to describe. The upper snowpack remains complex and contains persistent weak layers and our areas of greatest concern are also areas where recent winds have stiffened surface snow and built larger slabs. While this structure continues to be found, very hard surfaces have made it much harder to trigger an avalanche. If you happen to find the wrong spot today, a resulting avalanche is likely to be a hard slab. It is important to remember that hard slab avalanches often break without warning, fracturing above you, and propagating quickly. Keep in mind that even a small avalanche can have large consequences in complex and challenging terrain.

Beyond the concern for isolated instabilities today, field observations have also been highlighting challenging and variable surface conditions. Widespread areas of windboard ranging in thickness have been reported at all elevations. Tools like boot and/or ski crampons and an ice ax may be necessary equipment depending on where you wish to travel.

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