Bollettino valanghe

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Avalanches large enough to bury a person are possible at upper elevations and on shaded middle-elevation slopes facing W-N-E. You may not observe obvious warning signs like snowpack cracking or collapsing before triggering a slide.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    You could trigger 1.5-2.5 foot thick avalanches that fail on buried persistent weak layers near the bottom of the snowpack. These weak layers exist on upper elevation slopes and most middle elevation slopes facing W-N-E. You'll find a stack of weak, sugary facets on shadier slopes. On sunnier slopes, the weak layers present as a variable series of crusts and facets. 

    Obvious signs of instability, like cracking and collapsing of the snowpack, have decreased. This doesn't mean the problem has gone away. Tracks on a slope are not indicators of stability — Several skiers or riders can descend a slope only to have the next person trigger an avalanche.

    The best way to manage this problem is to avoid avalanche terrain where denser slabs rest above weak, older facets and crusts. Short of that, you can reduce your risk by avoiding recently wind-loaded slopes, large avalanche paths, and those with ugly consequences if you are caught in a slide. 

Avalanche Discussion

Triggering an avalanche on weak snow layers near the base of the snowpack is still the main concern. The good news is that conditions are improving. Extended periods without significant snowfall allow this problem to gradually improve. It's been several days since the last large, reported avalanche (photo). Obvious signs of instability involving this weak snow, like snowpack collapsing, are becoming the outlier rather than the norm.

While the weak layers themselves still look ugly (Cape Horn, Smiley Ck), many observers report that the Idaho Facet Machine is slowly destroying the integrity of the overlying slab limiting its ability to effectively propagate a fracture. Loose snow avalanches were triggered each of the last two days near Galena Summit, a sign that in some locations, faceting has turned a large portion of the snowpack to a pile of weak sugar.

We're moving the stability needle in the right direction but far from throwing caution to the wind. Weak snow layers near the base of the snowpack should continue to drive your terrain choices. Steep slopes with stiff, recent wind drifts are the most suspect. The consequence of any slide is much greater in large avalanche paths or complex terrain with terrain traps like trees, rocks, or creek bottoms. 

Regioni coperte