Bollettino valanghe

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Sawtooth Avalanche Center
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Pericolo valanghe

Tue
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

You're most likely to trigger a large avalanche where the wind formed large drifts or stiffened the snow surface, especially in steep rocky terrain. Smaller, loose snow avalanches are possible on sunny slopes when the surface snow is moist or mushy. Triggering large avalanches is unlikely where the snow surface is powdery (very soft and dry).

Problemi valanghivi

  • Loose Wet

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

    What and where is it? The chance of relatively small, natural and human-triggered wet loose avalanches will increase on slopes that check most or all of the following boxes:

    • Receiving direct, unobstructed sunshine.
    • Sheltered from the wind.
    • Very steep (approaching or over about 40 degrees).
    • Near exposed rocks.

    How can we recognize and manage this problem? The threat of wet loose avalanches generally follows the sun around the compass: SE-S aspects in the morning, S-SW facing slopes mear mid-day, and SW-W aspects in the afternoon. Watch for rollerballs and pinwheels, signs the surface snow is becoming moist and wet loose avalanches may follow. These slides often initiate near the base of trees and rocks, gathering snow and growing in size as they move downhill. While generally small, these slides could knock you off your feet or push you where you don't want to go.

    (1/11/2026) Rollerballs and small, natural wet loose avalanches in the northern Boulder Mtns, Pole Ck drainage. SW aspects in alpine terrain. 

    Photo: Sawtooth Avalanche Center

  • Wind Slabs

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

    What and where is it?  You may be able to trigger 1-3 foot thick slabs in wind-loaded, upper elevation terrain. Some slabs overlie crusts and/or thin layers of weak, faceted snow; the slabs could break wider than expected. Triggering these large avalanches is most likely on "prime time" slopes angles for slab avalanches—slopes approaching or exceeding about 40 degrees. 

    How can we recognize and manage this problem? The wind slabs are fairly easy to spot and avoid. Watch for smooth pillows below ridgelines and cornices as well as on the sides of cross-loaded gullies and on the aprons of large chutes and couloirs. Dunes and ripples on the surface are clues the wind has been at work transporting snow, and cornices falling are great triggers for the wind slabs below them. If you feel the snow surface 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 sound hollow, like a drum, and behave unpredictably; they can break above you and wider than expected. 

     

     

     

Avalanche Discussion

Last week, skiers triggered slab avalanches in steep, wind-affected terrain in the northern and southern Sawtooth Mtns. In recent days, we and other observers saw several large avalanches that released at the end of, or following, the early January storms (see photos below). Some general characteristics of these slides:

  • They occurred in wind-loaded terrain in the wetter, snowier parts of the forecast area (to the south of this zone).
  • They appeared to be triggered by cornices or smaller avalanches coming from above. 
  • They released on SE-E-NE aspects near and above 8500'. 

Tragically, three people were killed in avalanches in recent days in neighboring states. A snowmobiler was killed SE of Afton, Wyoming on Sunday (view limited information here). Last Friday, a Washington avalanche caught four skiers and killed two (more information).

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