Bollettino valanghe

Eastside Region

Eastern Sierra Avalanche Center
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Pericolo valanghe

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

In sintesi

If you venture into steep exposed terrain you may encounter dense, textured slabs of drifted snow. Fresh drifts will be most sensitive, while older, larger slabs will be more stubborn. Safer, softer snow can be found in sheltered terrain. The hazard will rise late this afternoon and overnight as new snow begins to fall.

Problemi valanghivi

  • Wind Slabs

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

    Strong southwest wind will build fresh slabs with whatever loose snow is left to transport today. Smaller, more sensitive drifts will be interspersed across terrain with larger, more stubborn wind deposits. Look for areas of blowing snow and be wary of steep slopes below. Terrain features that encourage drifting such as the leeward sides of ridgelines, gully features, and cross-loaded depressions deserve extra caution. Watch for cracking in hollow, stiff surface snow as a warning sign. While most concerning near and above treeline, strong winds can redistribute snow in unexpected ways. Don’t be surprised to find wind deposits in isolated areas below treeline and further down slopes than you may typically expect. It’s a good day to find the most sheltered terrain you can. That’s where the safest and best riding will be.

    (1/6/2023) Photo: Cracking in wind slabs

Avalanche Discussion

Numerous large avalanches failed during the last storm on Thursday. These were primarily below ridgelines on leeward slopes. The last confirmed avalanche failing on buried weak layers occurred on New Year’s Day during a rain event. It was intentionally triggered by explosives while June Mountain Ski Area was closed. 

The upper snowpack has been settling and stiffened by the wind. An older generation of wind slabs covers the surface in exposed terrain near and above treeline. Sheltered areas still hold unconsolidated snow. Rain crusts from late December storms exist in the lower snowpack up to about 9500 feet. Underneath, weak layers from late November and early December are buried 2 to 3 meters deep. These layers were wetted below treeline during the last rain event.  On a regional scale, persistent slab avalanches have become isolated and unlikely.  A larger trigger such as a breaking cornice or a large wind slab avalanche may be required to initiate a failure in deeper weak layers. Intense new loading next week could bring the problem back to the forefront. Deep, very large natural avalanches may again become possible. 

Strong to extreme winds will find whatever soft snow is left to transport today and build new slabs in exposed areas. The hazard will rise as new snowfall provides a fresh round of ammo for the wind slab machine late this afternoon and overnight. 

Regioni coperte