Bulletin d’avalanche

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Danger d’avalanche

Thu
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 2 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

You're most likely to trigger a large avalanche on steep slopes facing the northern two-thirds of the compass. In recent days, multiple groups triggered avalanches remotely—from flat terrain below, above, and to the sides of steep slopes—to the southeast of this zone.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–2.5

    Slabs formed in early February rest above a variety of ugly, widespread, weak layers (facets, surface hoars, crusts, and combinations). You are most likely to trigger a 2-4 foot thick avalanche where:

    • The slope or terrain you're 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.

    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, break wider than expected, and release above or hundreds of feet away from where they are triggered. We can't assume tracks on a slope mean it is safe; several people could descend a slope before triggering an avalanche.

Avalanche Discussion

Countless avalanches released naturally in the southern part of this zone (the western Smoky Mtns and southern Sawtooths) during the big February storms. Fewer avalanches released in the northern Sawtooths near Stanley. Avalanche conditions appear to be diverging in this zone. 

In and near the southern part of the zone: Sunday, skiers remotely triggered avalanches near Galena Summit (first-hand report, SAC site visit) and in Lake Creek (first-hand report, SAC site visit) while skiing low-angle terrain next to steeper slopes. We also received a report of a recent large avalanche in the Mt. Baldy backcountry that appeared to be remotely triggered by skiers. We continue to receive reports of booming collapses from around the forecast area.  This clear evidence shows the snowpack needs more time to adjust to the big load from the recent storms. 

In the northern Sawtooths: In recent days, professional and public observers reported fewer obvious signs of instability. However, a ski guide reported a snowpack collapse that "was definitely [one of the] top 3 loudest collapses I have ever heard." Similar to conditions in the Banner Summit zone, you probably would not see obvious signs of instability (cracking, collapsing, recent avalanches) before triggering a large avalanche.

Consider the consequences of a meaty slab avalanche breaking hundreds of feet wide before committing to playing on or below any steep slopes with trees, creeks, lakes, or gullies where the debris would pile up.  

Régions couvertes