Boletín de aludes

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Peligro de aludes

Sat
Alta montaña
1 · Débil
Límite del bosque
1 · Débil
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 7 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Avalanches are unlikely and most slopes are safe. Isolated areas of unstable snow may exist on very steep slopes, particularly at elevations above 9,000'. Be on the lookout for areas where stiff, wind-drifts overlie weak, sugary snow near the ground. 

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    1–2

    The last significant, reported avalanche in this zone occurred on February 6th when ski patrollers at Bald Mountain intentionally triggered an avalanche during mitigation work before opening the ski area. The slide failed on a wind-loaded slope that sees little ski traffic and harbored weak, sugary, faceted snow in the lower part of the snowpack.

    This exact snowpack scenario—hard, wind-drifted snow overlying weak, faceted snow—is where you're most likely to find unstable conditions today. These slabs often form downwind of prominent terrain features and can sound "drummy" or feel hollow beneath your skis or sled. While triggering a slab avalanche is unlikely, I'd still pay attention in very steep, recently wind-loaded terrain, especially at elevations over about 9000'.

Avalanche Discussion

LOW Danger: The Banner Summit and Wood River Valley & Soldier Zones are at LOW danger. When the danger is LOW triggering an avalanche is unlikely and most slopes are safe. Could you trigger an avalanche at LOW danger? Certainly, but you'd have to find one of the very few spots in the range with unstable snow. If you dropped 50 people off and told them to ski or ride the steepest, wind-loaded slopes they could find, someone would probably trigger a slab avalanche. It's nearly impossible to definitively predict which slope(s) are "triggerable", but we can hedge our bets by thinking about the consequences of small avalanches where we're playing. If you don't like the looks of what's below you—trees, cliffs, roads or other terrain traps—then move to a different part of the slope or another area altogether.

Looking Ahead: A passing cold front this morning will kick off a blustery, cold, and snowy weekend. Snowfall amounts in the next couple of days will be light, but it can be surprising how quickly fresh slabs can form with a persistent wind. Snowfall will increase Saturday night and weather models predict around a foot of new snow in some portions of the Banner Summit and Sawtooth & Western Smoky Zones by Sunday afternoon.

Our field objectives over the last couple of days included checking in on the snow surface to get a better sense of what this snow will rest on. You can read Chris and Martins' thoughts from yesterday near Williams Peak in the Sawtooth Mountains here. They concluded, "I could see some potential instability with the weekend storm but it doesn't seem likely that it will be extensive or long-lived in this area. "

Wednesday, in the Soldier Mountains, the conditions were very different. I found an ugly and relatively widespread crust and facet combination at middle elevations (video). Warm temperatures at the end of January and early February built a stout crust. Since then–unlike the snowier regions to the north–the Soldiers received very little snow. In sheltered areas, this tiny amount of snow was allowed to facet and surface hoar sprang up on shaded slopes. 

I highlighted these two examples to help point out the spatial variability we might expect with this weekend's storm. By late winter and spring, temperatures near or above freezing, heavier and more localized precipitation events, and strong solar radiation can produce a wide range of conditions over a short distance, not to mention zone-to-zone. As you head out to enjoy the snow, keep this variability in mind and frequently check-in to see how the new snow is bonding with the old snow surface. 

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