Bollettino valanghe

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

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

You're most likely to trigger a large avalanche on steep slopes facing the northern two-thirds of the compass, especially in the southern part of this zone where the snowpack is less deep. Watch for and avoid fresh, stiff wind drifts throughout the zone. Any extended sunshine will increase the likelihood of loose avalanches today. Choose more conservative terrain if obvious signs of instability, such as cracking or collapsing, are present.

Problemi valanghivi

  • Wind Slabs

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

    Wind Slab: Isolated wind slabs up to 2 feet thick formed in recent days. The slabs could rest above weak crust and facet combinations on southerly aspects or small sugary facets on more north-facing slopes - this could make avalanches both easier to trigger and wider than you might expect. You're most likely to find the slabs immediately beneath exposed upper elevation ridgelines and on the sides of cross loaded gullies.

    Loose snow avalanches: If you're playing in very steep terrain, expect to trigger sluffs involving the 1 - 2 feet of snow that has fallen over the past few days. Expect natural loose snow avalanche activity to increase quickly on slopes that receive direct sunlight. Avoid spending time below large cliff faces, very steep chutes and couloirs. Be aware of where a smaller avalanche may take you, and avoid riding in avalanche terrain above terrain traps such as gullies, creeks, and thick timber. 

    *These new snow avalanches may "step down" into deeper buried weak layers (problem #2) resulting in much larger avalanches.

    (2/15/2025) This natural wind slab avalanche released naturally on Feb 14 or 15 in the Goat Ck drainage. SE aspect near 10,000'. The slide may have been triggered by cornice fall. It appeared to involve the snow that fell on Feb 13-14. 

    Photo: Sawtooth Avalanche Center

  • Persistent Slabs

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

    Although the slabs that formed in early February seem to be stabilizing, they rest above a variety of ugly, widespread, weak layers (facets, surface hoar, crusts, and combinations). Before triggering an avalanche, you may or may not 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:

    • A smaller wind slab or loose snow avalanche overloads the buried weak layers (problem above)
    • 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
    • The slab is less than about 3' thick—relatively shallower spots may exist where the wind frequently blows, and the slab is not uniformly thick.

    (2/17/2025) The crown of the E aspect persistent slab avalanche on Sun Mountain.

    Photo: Sawtooth Avalanche Center

Avalanche Discussion

Although we've dropped the likelihood of triggering a large persistent slab avalanche to unlikely today to match the general trend we're seeing from observations, this change should be taken conservatively. You are most likely to trigger an avalanche where the slab is less than 3 feet thick, where buried weak layers may be more easily affected by your sled, skis or snowboard. The drainages around Smiley Creek are an example of locations where we suspect these thinner, less-stable snowpacks exist. On the other hand, the northern and western areas of the Sawtooth and Western Smokys zone have deeper snowpacks, and we've found fewer signs of instability there in recent observations.

Triggering a wind slab or loose snow avalanche is probably the easiest way to awaken the dragon and trigger a deeper, larger persistent slab avalanche. Be on the lookout for wind-affected snow surfaces and sun-induced natural loose snow activity, and think about the consequences of getting caught in one of these smaller wind slabs or loose snow avalanches.

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