Lawinenlagebericht

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
3 · Erheblich
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Conditions are dangerous at upper elevations. Expect to trigger large, 1-3 foot thick avalanches where the wind has drifted snow or stiffened the snow surface. Avalanches may release naturally. Triggering similar slides in more sheltered terrain is not out of the question. 

Conditions are less dangerous in the mountains near Carey, Hailey, and Ketchum where less snow fell recently.

 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    What is it?  You are likely to trigger a 2-3 foot thick soft or hard slab today in the western portion of this zone (see Forecast Discussion). Overnight winds picked up and created sensitive slabs. On Friday, professionals in the Soldiers triggered a 1-foot thick wind slab with explosives. On Saturday, a rider in the Pole Creek drainage triggered a large wind slab that broke above them on the slope they were riding (observation here). Importantly, these slides occurred before the added load from this storm.

    Where is it? You'll be most likely to find slabs near ridgelines and mid-slope terrain features like ribs and gullies. Winds likely created these slabs on features in the middle elevation.

    How can you recognize it? Cracks shooting out from your skis or sled clearly indicate instability. Watch for drifts, dunes, and ripples on the snow surface. Wind slabs can have a smooth, chalky appearance and feel and sound hollow, like a drum. Wind-deposited snow will be stiffer and keep your skis or snowmobile on or closer to the surface. Some of these slabs might be masked by recent snow and be more hidden.     

    How can you manage it? You can significantly reduce your risk today by steering clear of wind-loaded terrain. Today's slabs might not behave like your "typical" wind slab. Various weak layers exist in the snowpack's upper 2-3 feet (watch the video at right/above). Because of this weak snow, today's slabs may break wider and deeper than expected from a "simple" wind slab.

Avalanche Discussion

Avalanche conditions have diverged in this zone between the western and eastern areas. Overnight a storm brought in moderate to strong winds, with at least 10 inches falling in the Soldier mountains and Dollarhide summit. Snowfall will continue through the day, with winds moving it into thicker slabs. In this part of the zone, wind slabs will be more sensitive to the weight of your skis or sled and need to be treated with extra caution. Harboring down below this new snow is a mess of hardpack crusts, facets, and crust with facets. Triggering a wind slab today has the potential to step down into these weak layers and cause a bigger avalanche than expected. 

In the mountains surrounding the Wood River Valley and Carey, you are less likely to experience the same severity of avalanche danger as in the western mountains. The storm brought 4-6 inches of new snow with the same moderate winds. This area has a wide variety of surface conditions, from bare dirt to well-developed faceted snow to rock-hard crusts pounded by the wind. Focus on the following issues for this portion of the zone:

  • Wind Slabs: New snow and winds have created fresh slabs in exposed middle to upper elevations. On Sunday, a group experienced large collapses along an exposed ridgeline. These slabs can also be found on the side of gullies or chutes, and near prominent features. You may encounter cracking or collapsing, which is a sign of unstable snow. Any slabs you find are most suspect on slopes steeper than about 35 degrees. 
  • Loose Snow Avalanches: The upper snowpack is fragile and filled with surgery, faceted snow, especially on sheltered slopes facing NW-N-NE. On very steep slopes approaching 40 degrees, getting surface snow moving and picking up speed won't take much. The hazard is most concerning on slopes that end in rivers, cliffs, trees, or other terrain traps
  • Persistent Slabs: You would need bad luck to trigger a rogue large avalanche on weak, sugary snow at the bottom of the snowpack. To reduce the odds of this scenario, you can avoid very steep avalanche terrain (approaching 40 degrees) with large, hard wind features that keep you on the snow surface.

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