Bollettino valanghe

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

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Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
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In sintesi

Heavy snowfall and wind-drifting are creating very dangerous avalanche conditions. Natural and human-triggered avalanches are almost certain. Stay off of and out from below all steep slopes. Avalanches can be triggered remotely—from below, above, and to the sides of steeper terrain.

Problemi valanghivi

  • Persistent Slabs

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

    Today's snowfall and wind-drifting are stressing weak, faceted snow buried over 3' deep. This weak layer has been the culprit in almost all of the avalanches we've observed this season. Continued heavy snowfall and wind-drifting are pushing this weak layer to the breaking point. This avalanche occurred yesterday above Titus Lake near Galena Summit. It was likely triggered remotely from the low angle ridgeline above. 

    I urge you to steer clear of all avalanche terrain. Remotely-triggering slides, from flat terrain below steep slopes, is a real possibility. Two years ago, and with conditions very similar to today's, a skier and a snowboarder were caught, carried, and buried in a slab avalanche outside the ski area boundary on Bald Mountain. Remember that once you duck the rope you're entering terrain that's unpatrolled and uncontrolled. 

  • Storm Slabs

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

    This zone has received up to 3-5' of snow (2.1-3.6" SWE) since Tuesday night! Air temperature has continued to warm slightly as the snow piles up which aids in the formation of top-heavy slabs of snow on many aspects. These slabs are forming on a variety of weak snow surfaces including facets, crusts and facets, surface hoar, and wind-hammered ice. Observers in the Soldiers, the Wood River Valley, and the Sawtooths (photo) have found very sensitive slabs of new snow, failing on a layer of facets above a crust.  

    Moderate to strong SE wind has moved a substantial amount of snow at all elevations. Expect slabs to be thicker, stiffer, and more dangerous in windier terrain. Areas of wind-drifted snow may be hard to identify due to low visibility and continuing snowfall. This problem will become more dangerous as snow and wind continue throughout the day. These slides have the potential to "step-down" causing avalanches to fail on more deeply buried weak layers near the ground (see Persistent Slab problem).

    (1/28/2021) Crowns of avalanches that failed during the ongoing storm in the Warm Springs drainage and buried a portion of the road with debris.

Avalanche Discussion

AVALANCHE WARNINGS are in effect for the Sawtooth & Western Smoky, Galena Summit & Eastern Mountains, and Soldier & Wood River Valley Zones.

Very dangerous avalanche conditions exist. Large, destructive, natural, and human-triggered avalanches are near certain. There are a host of scenarios that could send large avalanches hurtling down steep slopes today. Our snowpack has touchy weak layers under the recent storm snow, as well as a remarkably weak foundation of faceted snow. Expect avalanches to occur on many slopes, potentially breaking in unusual locations and wider than expected. 

Yesterday's observations were limited by difficult travel and poor visibility. Despite that fact, we didn't need to look for avalanches as much as we just needed to stay out of the way. Here are some notable events from yesterday:

  • Sun Valley Ski Patrol reported numerous natural and explosives triggered avalanches in closed terrain. The largest slide was triggered by explosives in their expansion terrain. The avalanche ran 1,700 vertical feet, extending further than it's run in over 30 years. 
  • The Soldier Mountain Cat Ski operation reported explosives triggered avalanches in the Soldier Mountains. 
  • Large, natural avalanches crossed Warm Springs Road west of Ketchum.
  • A natural slab avalanche partially blocked Hwy 75 near Galena Summit. 
  • Numerous small avalanches were triggered remotely by riders near Pine, just west of our Soldier & Wood River Valley Zone. 
  • Snowpack collapsing and cracking were widespread. Some collapses traveled to steep slopes, releasing avalanches near Galena Summit and shattering small slopes in the Wood River Valley. 

Snowfall will diminish today, but avalanche conditions will remain very dangerous. Avoid all avalanche terrain. This includes flat slopes in the valley bottom that are threatened from above.

Regioni coperte