Bollettino valanghe

Banner Summit

Sawtooth Avalanche Center
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Pericolo valanghe

Sun
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 8 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Conditions become dangerous as you climb into windy terrain. You can reduce the odds of triggering a large avalanche by avoiding slopes with stiff, wind-drifted snow at the surface. Triggering a much larger, 3-5 foot thick slab avalanche is far less likley but not out of the question.

Problemi valanghivi

  • Wind Slabs

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

    Expect to find fresh wind drifts and slabs up to 3 feet thick in exposed, upper-elevation terrain.  Today's strong wind and snowfall could produce natural avalanche activity. Watch for dunes or smooth pillows below ridgelines and cornices and on the sides of cross-loaded gullies.

    Fortunately, the fresh wind slabs should be easy to spot and avoid. If you feel the surface snow getting stiffer, move to gentler terrain. Cracks shooting out from your skis or sled are an obvious sign that you've found a wind slab. Natural releases and human-triggered slides have the potential to trigger the much larger Persistent Slabs described below as the wind slab avalanche moves downslope.

    (12/18/2025) We found natural avalanches on the NE slope of the summit of Copper Mountain (8900 ft). These appeared to have released on Dec 17th and looked to be thin wind-slabs. Photo: Sawtooth Avalanche Center

  • Persistent Slabs

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

    Weeks of heavy, dense snowfall, rain, and warm temperatures formed thick, meaty slabs on most middle and upper elevation slopes. Multiple crusts may be buried in the upper 3 feet of the snowpack, providing possible failure layers where the crusts are relatively thin.

    Assume the slab + weak layer (crust) setup exists on all slopes until proven otherwise. You may not experience obvious signs of instability—like snowpack collapsing or cracks shooting out from your skis or sled—before triggering an avalanche. 

    As you change elevation and aspect, or travel through different drainages, you'll see significant variability in the buried crusts. This uncertainty makes it challenging to accurately predict which slopes could still cause trouble. There's an outside chance you could trigger avalanches remotely—from flat terrain below, above, and to the sides of steep slopes. 

    Additional Discussion: Weak, sugary, faceted snow in the bottom third of the snowpack is now buried 3-6 feet deep on W-NW-N-NE-E-SE facing slopes at middle and upper elevations. Triggering a huge slide on these layers is unlikely but would be unsurvivable. You're most likely to poke this beast in windy and/or rocky areas where the snowpack depth is variable.  

    (12/20/2025) Natural avalanche on an E aspect near 8900 ft in the Beaver Ck drainage in the western Smokys.

    Photo: Jeremy Lato

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