Bollettino valanghe

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

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

Triggering a large slab avalanche is most likely on steep slopes facing the northern two-thirds of the compass, especially in the southern part of this zone where the snowpack is thinner. Sluffs involving the surface snow may release naturally on very steep, slopes basking in direct, unobscured sunlight. 

Problemi valanghivi

  • Loose Wet

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

    Avalanches are most likely on very steep, rocky slopes receiving direct sun. These slides often initiate near the base of trees and rocks, gathering snow and growing in size as they move downhill. Rollerballs, or pinwheels, signify that the snow is heating up, and wet avalanches may soon follow.  

    While most will start small, they will be plenty large enough to knock you off your feet and carry you into unwanted terrain. Even small loose snow avalanches are consequential above terrain traps such as gullies, creeks, and thick timber. Plan your day to avoid lingering under steep, sunny slopes when the sun is out.

    (2/20/2025)

    Numerous wet loose avalanches in the SE bowl of Williams Pk. Many slopes have shed recent storm snow—but not all, and similar avalanches are possible in very steep wind-sheltered, sun-drenched slopes. 

    Photo: Sawtooth Avalanche Center

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–2.5

    Slabs that formed in early February rest above a variety of ugly, widespread, weak layers (facets, surface hoar, crusts, and combinations). Before triggering an avalanche, you're unlikely to experience obvious signs of instability like snowpack cracking and collapsing or whumpfing. Persistent Slabs can release in surprising ways and break much wider than expected. You are most likely to trigger a dense, 2-4 foot thick avalanche where:

    • The snowpack is less than about 4 feet thick—relatively shallower spots may exist where the wind frequently blows, and the slab is not uniformly thick.
    • Any part of the slope you are on or connected to is steeper than about 35 degrees
    • The slope faces the northern 2/3 of the compass
    • A smaller wind slab or loose snow avalanche overloads the buried weak layers

    (2/17/2025) Avalanche on Sun Mountain in a thin snowpack near Ketchum.  Photo: Sawtooth Avalanche Center

Avalanche Discussion

Triggering a large persistent slab avalanche is unlikely but not out of the question—especially in areas where the wind frequently blows and the snowpack depth is variable. The drainages around Smiley Creek are examples of locations where we suspect these thinner slabs exist. We've found fewer signs of instability in the deeper portions of this zone, including the northern and western Sawtooths and the western Smokys. 

Many steep, sun-drenched slopes shed recent snowfall after yesterday’s strong sun, though some very steep slopes basking in direct sunlight may still harbor enough ammo to release naturally with today’s continued sunshine. You can hedge your bets by avoiding lingering under these slopes soaking in the sun or seeking cooler slopes if you find a mushy, wet snow surface. In alpine terrain, thin wind slabs may linger, watch for signs of wind-drifted snow or instability, such as snowpack cracking or collapsing. 

Regioni coperte