Boletín de aludes

Banner Summit

Sawtooth Avalanche Center
Ver en el mapa

Peligro de aludes

Fri
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
Open full map
Desactualizado: este boletín caducó 8 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Recent snow and wind created dangerous avalanche conditions in windy terrain. You can reduce your odds of triggering a wind slab avalanche by avoiding slopes with stiff, wind-drifted snow at the surface. Triggering a much larger, 2-3 foot thick slab avalanche remains a possibility in both sheltered and wind-loaded terrain. 

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1.5–2

    Expect to find fresh wind drifts and slabs up to 2 feet thick in exposed upper elevation terrain. Watch for dunes or smooth pillows below ridgelines and cornices and on the sides of cross-loaded gullies. Cracks shooting out from your skis or sled are an obvious sign that you've found a wind slab. 

    Fortunately, the fresh wind slabs should be easy to spot and avoid. If you feel the surface snow getting stiffer, move to gentler terrain. Any wind slab you trigger has the potential to trigger the much larger Persistent Slabs 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 montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    2–3

    Several days of heavy, dense snowfall, rain, and warm temperatures formed thick, meaty slabs on most middle and upper elevation slopes. Multiple crusts are buried in the upper 3 feet of the snowpack, providing possible failure layers for the slabs above. 

    Assume the slab + weak layer setup exists on all slopes. You may or 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 are trouble and which are safe to ski or ride. You may be able to 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

Avalanche Discussion

Avalanche conditions are tricky. They vary from drainage to drainage and can change quickly as you round the compass or climb in elevation. Why? Over the past 10 days, we've added over 6" of water to the snowpack, more than the previous 2 months combined! This heavy precipitation fell with punctuations of extreme wind and wild temperature fluctuations that sent rain lines above 9,000' on multiple occasions. These rain-on-snow events saturated the snowpack in some middle and low elevation areas, which will ultimately be a good thing for stability once it firms up again.

Climbing in elevation separates these rain layers with layers of snow, building a complex array of crusts or possibly crust + facet combinations as you climb in elevation. The variability here adds a healthy dose of uncertainty. Underneath it all lurks the most prominent weak layer of the winter, a stack of facets that should not be forgotten about in areas where the snowpack depth is around 3' deep, or in steep, rocky terrain where the snowpack depths are variable. 

Enjoy the snow this holiday, but know that when conditions are complex, you can always choose simpler, lower-consequence terrain.

Regiones cubiertas