Bollettino valanghe

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

Fri
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3 · Marcato
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2 · Moderato
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In sintesi

Natural and human-triggered avalanches were reported at middle and lower elevations yesterday. Avoid steep slopes with wind drifts or stiff snow on the surface to reduce the chances of triggering an avalanche. Although not likely, some avalanches could fail on layers deep in the snowpack releasing a slide large enough to snap trees or destroy a vehicle.

Conditions are more dangerous near the Smoky Mountain crest/Dollarhide Summit where Storm totals are greatest. Refer to the Galena Summit & Eastern Mtns Forecast if you're traveling in this area.

Problemi valanghivi

  • Wind Slabs

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

    Snowfall in this zone has heavily favored the Smoky mountain crest near Dollarhide Summit where ~2' of snow (2.2" SWE) fell since Monday night. By contrast only 7-10" of snow fell in the hills around the Wood River Valley. Despite low snow totals, small, natural and skier-triggered avalanches were reported above the Wood River Valley yesterday.

    Expect to find wind slabs, large drifts, and cornices in upper elevation and exposed middle elevation terrain. Triggering a wind slab is possible near ridgelines, beneath cornices, and on the sides of cross-loaded gullies. Strong wind has mixed down into valley locations as well, so don't be surprised to find stiffer, wind-drifted snow near the mouths of main drainages, along Highway 75 and near prominent terrain features lower on slopes.

    Some of the wind slabs may have formed above weak snow in the upper part of the snowpack and could be more sensitive to triggering than you would expect. Cracks shooting out in front of you are a clear sign you could trigger wind slab avalanches. Pay attention to how the snow feels beneath your boards or sled. If you feel the snow stiffen or notice you're staying closer to the surface instead of sinking deep into the snowpack, you've found wind-affected snow and should avoid steep slopes. 

    Additional Discussion:Temperatures climbed steadily through the night and will reach near 40 F at the lowest elevations today. This warming could cause rapid settlement in recent storm snow enhancing your chance of triggering a slab avalanche on even wind-sheltered slopes at low elevations. These avalanches should be small but can have big consequences if they drag you into a terrain trap like a road cut or a creek bottom. These problems are most likely near Dollarhide Summit where more snow fell. 

    (1/5/2022) These small drifts were observed Wednesday in out-of-bounds terrain near Baldy.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    A mix of facets and crusts leftover from October snowfall make up the base of the snowpack on some shaded middle and upper elevation slopes. This old snow is most prevalent near Dollarhide Summit and in the Soldiers. Avalanches have failed on this layer during each major precipitation event. 

    The ongoing snowfall and wind are stressing the old October weak snow. The mountains near Dollarhide may be the "sweet spot" today where heavy snowfall and weak layers near the ground combine to produce some big avalanches. While we don't anticipate widespread avalanche activity on this layer, it's nearly impossible to predict exactly which individual slopes are teetering on the edge.

    How are local professionals managing this problem? They are generally taking it off the table by avoiding slopes where the old snow exists. This travel strategy is pretty easy to swallow given the excellent riding and skiing conditions on slopes lacking the old October faceted snow.  

    (1/2/2022) This large persistent slab avalanche was observed above Corral Creek, near Johnstone Peak. It failed on a N/NW facing slope at 8,600'. The terrain and trees below the crown limited its size, but the crown is over 500' wide.

Avalanche Discussion

Yesterday, snowfall along the Sawtooth and Smoky mountains just didn't want to quit. Storm totals since Monday evening are pushing well over 2' and will surpass 3' by the end of the day. As a result, the danger in the Sawtooth & western Smoky Mountains Zone has bumped to HIGH. Large, natural avalanches are likely and avalanche terrain should be avoided. Honorable mentions in neighboring zones include Dollarhide Summit and Galena Pass where similarly dangerous avalanche conditions exist. A sharp gradient in snowfall occurs as you move to the east and south of the Smokys. Far less snow fell in our southern and eastern mountains but dangerous avalanche conditions exist in winder terrain. 

Unlike the disparate snowfall amounts across the zones, it's been windy everywhere. Yesterday it sounded like a category 3 hurricane on top of Baker Pk. The Peak 2 weather station in the Soldiers recorded a gust of 123 mph and gusts topped 100 mph in 7 of the last 24 hours. Observers reported wind-blown snow anywhere from the high peaks to Highway 75 and the foothills above the valley floor. This wind affect built sensitive wind slabs yesterday, some of which failed naturally or were triggered by skiers. It also stiffened the snow surface on many slopes, increasing the odds of triggering a smaller, soft slab avalanche on some steep slopes. 

The final twist? It's eerily warm out there. Today's high temperatures will reach 40 F near Fairfield, Hailey, and Stanley. Near or slightly above freezing temperatures will also creep into middle elevations. This warming will act to condense the slab, stiffening the snow surface and creating top-heavy slabs on some lower elevation slopes. These slabs may peel off naturally or be sensitive to your weight. There's a lot of uncertainty here, amplified by the weak, shallower snowpack at lower elevations. Across the board, it's good to realize that conditions may change quickly as the day warms. Related to this concern, is the often overlooked hazard of roof avalanches. I saw a few steep, metal roofs release yesterday afternoon. If yours hasn't shed its snow, there's a good chance today is the day. 

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