Bollettino valanghe

Banner Summit

Sawtooth Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
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

Triggering a large, dangerous avalanche is a real possibility. You may or may not see or hear warning signs before triggering a thick, wide slide. These slides can be triggered from gentle terrain above, below, or to the sides of steep slopes.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    The odds of triggering large, Persistent Slab avalanches are decreasing, but the consequences remain severe. Expect to find 1-2.5 foot thick slabs in areas sheltered from the wind. The slab may be twice as thick in terrain affected by the wind. These avalanches have failed on various weak layers: facets and/or surface hoar on shadier aspects and crust + facet combinations on sunnier slopes. Large natural and human-triggered avalanches have occurred on several aspects in recent weeks. Assume this problem exists on all upper and middle elevation slopes and on shadier, lower elevation aspects.

    Avalanches on this uncommonly widespread and fragile layer will break widely and in surprising ways. Don't expect obvious signs of instability, like snowpack cracking and collapsing. Your first sign of trouble may be the destructive avalanche you trigger. These slides can be triggered from long distances away—from flat or gentle terrain below, above, or to the sides of steep slopes.

     

    (1/22/2024) The debris of this slide ran into a creek, a lower and mid-elevation terrain trap that is characteristic of the Banner Summit Zone. Terrain features like these multiply the consequences of these slides.

Avalanche Discussion

This zone has had little slab avalanche activity in the past week. Modest recent precipitation and a heavy, dense slab are allowing buried weak layers to slowly gain strength. While the chance of triggering a Persistent Slab avalanche is gradually decreasing, it is not zero. 

Unfortunately, accurately assessing which slopes are still teetering on the edge is quite difficult. You may get away with it. If not, you'll trigger a thick, unsurvivable slide that could span multiple terrain features. This outcome is a real possibility. Entering significant avalanche terrain remains a high-stakes roll of the dice. 

Regioni coperte