Bulletin d’avalanche

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Danger d’avalanche

Tue
Alpin
1 · Faible
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

A skier was caught and carried in a small wind slab avalanche in this zone yesterday. While large avalanches are unlikely today, even small avalanches can have high consequences. Triggering small dry snow avalanches—wind slabs and sluffs—is possible on steep slopes. The chance of wet snow avalanches will increase this afternoon when the sun comes out. Watch for the newer snow becoming moist and sliding on slick crusts. Near valley bottoms, expect to find wet, rotten snow by this afternoon. 

Problèmes avalancheux

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Below-freezing overnight temperatures and cloud cover this morning will keep wet snow issues at bay during the first part of the day. As skies clear, crusts that formed at the snow surface will quickly melt, bringing wet snow problems back to the table. There are two broad categories of wet snow problems to watch out for today:

    • Near-surface wet snow: Snowfall from over the weekend is sitting on icy crusts that formed during earlier warm-ups. As this snow melts this afternoon you may be able to trigger a wet loose avalanche as the new snow peels off the crust below. These slides will start at a point and fan out and pick up additional snow as they travel downslope.
    • Full-depth wet snow: At lower elevations, where temperatures are warmer, wet snow avalanches involving the entirety of the snowpack may be possible on very steep slopes by this afternoon. A rider in the Soldier Mountains yesterday reported that the snowpack at lower elevations had reached this state yesterday, and a snowshoer in the mountains above the Wood River Valley experienced a large collapse in a thin, wet snowpack on a shaded low elevation slope. Slides involving a snowpack that is weak, wet, and mushy will gouge down to the ground, producing an ugly, wet avalanche.  

    ADDITIONAL DISCUSSIONYesterday, a skier was caught and carried in a wind slab avalanche in the Soldier Mountains (photos and preliminary information here). The avalanche broke a reported 1-2' deep in a recently wind-loaded area. The western portion of this zone received more snow during the weekend's storm. This snowfall was accompanied by moderate to strong winds blowing out of the W-NW, building wind slabs in upper elevation terrain. Be on the lookout for similar slabs today and be alert to the consequences of being caught in even a small slide.

    (3/20/2021) Low elevation wet loose avalanche on a shaded slope. Warm Springs Road west of Ketchum.

Avalanche Discussion

Yesterday, a skier in the Soldier Mountains triggered and was caught in a wind slab avalanche. The slab broke in a heavily wind-loaded area, failing a reported 1-2' deep at the deepest part of the crown. Based on the location of the slide, it likely failed on a crust that formed during the warm, sunny weather last week. The skier was carried downslope until they got hung up on a small tree while the avalanche flowed around them. The skier's partner had already skied the slope without incident.

This avalanche is a perfect illustration of how we can find ourselves in trouble even during periods of LOW danger. Based on photos, this slide wasn't large enough to bury a person. However, being buried by an avalanche isn't the only way to have your day ruined by a slide. Obstacles like trees and rocks can become quite dangerous if we are carried into them at high speed. In this case, the tree that the skier was pinned against didn't cause any reported injuries, but the outcome could easily have been different. 

This event is a reminder for all of us that we are well-served to keep our guard up even when the avalanche danger is LOW. The mountains are an unforgiving environment, filled with hard objects that we don't want to encounter at high speed. Continue to practice the safe travel habits you've been using all season: travel one at a time, keep your eyes on your partners, and be conscious of the consequences of being caught in a slide in the terrain you are traveling in. 

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