Bulletin d’avalanche

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Danger d’avalanche

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

Points saillants

Very dangerous avalanche conditions exist. Large avalanches will release on their own in windy terrain. Avalanches will become more likely in sheltered terrain as the storm progresses. You could trigger slides remotely—from flat terrain below, above, and to the sides of steep slopes. 

Conditions are most dangerous where more snow fell in the western part of this zone, including the Soldier Mtns, Dollarhide Summit area, and headwaters of Warm Springs Ck.  

Problèmes avalancheux

  • Wind Slabs

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

    Expect to trigger 1-4 foot thick slabs in wind-loaded terrain. Avalanches could release naturallly, and cornices could fail and trigger slabs on the slopes below.  Avalanches could be wider than you expect, and very easy to trigger, due to persistent weak layers buried below the recent load from this storm. 

    The size and chance of avalanches will increase as the day progresses. Expect to find slabs near or just below ridgelines, along mid-slope ribs, and on aprons beneath chutes. Cracks shooting out in front of your sled or boards mean you've found a wind slab. 

    You can manage your exposure to this problem by identifying and avoiding wind-loaded slopes, including the gentler terrain below large, upper elevation starting zones.

    (2/1/2025) This natural avalanche released in wind-affected terrain on a N aspect near 9000' in the Frenchman Ck drainage, north of this zone. This avalanche likely failed on weak snow that formed during the January drought.  

    Photo: Allison Kinsler

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–2

    Many steep slopes that are even subtly wind-affected are approaching their tipping point; avoid all large or consequential avalanche paths where the wind has stiffened the snow. In areas sheltered from the wind, persistent slab and loose snow avalanches are possible. The size and chance of avalanches will increase as the day progresses. Possible drizzle and warm temperatres below about 7000' in the Wood River Valley mountains could cause avalanches to release naturally in very steep terrain.  

    The 15-30" of recent snowfall is stressing very weak snow that formed during the month long drought, including surface hoar, facets, and facet + crust combinations. These layers exist on many slopes, the worst of which are found at middle and low elevations. 

    A kiss of wind, rain, warm temperatures, or a brief bit of sun is all it takes to consolidate the storm snow into a touchy slab. Although smaller than the thicker wind slabs described above, this problem is tricky. Slabs may release in surprising ways and break wider than expected. You could trigger avalanches remotely—from above, below, or to the sides of steep slopes. It's hard to predict which sheltered slopes are unstable, so build a wide safety margin to handle the uncertainty. 

    Expect heavy sluffing on many steep slopes. Triggered slides of any form may quickly gain mass as they easily entrain the weak facets below, and large sluffs could trigger wider slab avalanches as they move downhill.

    (2/1/2025) Remote skier triggered avalanche in subtly wind-affected terrain in the western Smoky Mtns, north of this zone. As the slab builds and stiffens due to additional snowfall and wind, avalanches will become wider, thicker, and more frequent. 

Avalanche Discussion

Yesterday, Stanley set an all-time record for precipitation on Feb 1. Some areas in this zone are seeing similarly unusual precipitation totals. Part of the avalanche equation is simple today: very weak snow from a month long drought + unusually heavy precipitation + more snow on the way = AVOID ALL WIND-LOADED AVALANCHE TERRAIN.   

Despite yesterday's poor visibility and few observations, there were lots of signs of instability in neighboring zones (view complete Observation here): a natural avalanche and a remote triggered avalanche in the western Smokys, extensive cracking and collapsing in the northern Sawtooth Mtns, and collapsing in sheltered, lower elevation terrain near Cape Horn and Trap Ck in the Banner Summit area. Given the steady stream of moderate to heavy snowfall expected to continue, these observations should be viewed as foreshadowing of what's to come in this zone. 

Finding safe places to play is getting harder, and conditions are ripe for getting surprised. Enjoy the new snow, but pick your tours and rides carefully. Give large avalanche paths a wide berth, and don't underestimate the consequence of even smaller avalanches that could push you into terrain traps, such as thick trees, cliffs, and creek bottoms. 

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