Bollettino valanghe

Banner Summit

Sawtooth Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
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

The chance of triggering an avalanche rises as you climb into windy terrain. Avoid steep slopes with stiff, wind-drifted snow at the surface. 

Problemi valanghivi

  • Wind Slabs

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

    Strong winds formed hard and soft slabs up to 3 feet thick in upper and some middle elevation locations. Watch for smooth pillows, dunes, and large wind features below ridgelines and cornices as well as on the sides of cross-loaded gullies. Hard slabs may feel hollow and sound like a drum as you move across them. 

    How can we manage this problem? Fortunately, the fresh wind slabs are easy to spot and avoid. If you feel the surface snow getting stiffer, it's time to pay attention. Cracks shooting out from your skis or sled are an obvious sign that you've found a wind slab. Hard wind slabs behave unpredictably; they can break above you and wider than expected. 

    (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

    The highest odds of triggering Persistent Slab avalanches lies where you find concerning buried layers AND significant recent wind-loading. Weeks of snowfall, rain, and warm temperatures formed thick, dense slabs on most middle and upper elevation slopes. Multiple crusts and storm interfaces are buried in the upper 3 feet of the snowpack on many slopes, providing possible failure layers. 

    Triggering a large slide in windy or sheltered terrain is unlikely but not off the table. Assume the slab + potential weak layer setup exists on all slopes until you dig in the snow to prove otherwise. If you do trigger an avalanche, you probably won't experience obvious signs of instability—like snowpack collapsing or cracks shooting out from your skis or sled—beforehand. 

    As you change elevation and aspect, or travel through different drainages, you'll see significant variability in the buried crusts and storm interfaces. This uncertainty makes it challenging to accurately predict which slopes could still cause trouble. 

    Additional Discussion: Weak, sugary, faceted snow near the bottom 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. The best chance of poking this beast lies 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

Avalanche Discussion

Yesterday, strong wind made conditions downright unpleasant in upper elevation terrain on Copper Mountain. Above about 8500', surface conditions changed dramatically: hard slabs, scoured slopes, and overbuilt wind whales and features became common. The snowpack could behave unpredictably once you enter windier environments. 

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