Avalanche forecast

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Recent snow and moderate to strong winds make triggering a 1-2 foot thick avalanche possible today. You have a better chance of finding this issue in wind-drifted snow in exposed areas. Loose snow avalanches involving piles of weak, sugary snow are possible in steep, sheltered, shaded terrain.

The avalanche danger will increase tonight as the next storm arrives. Be careful if you’re out after sunset, especially in the western half of this zone.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    What is it? 1-3 inches of new snow fell yesterday and into the evening hours with up to 2 inches more today. Snowfall was accompanied by moderate to strong winds in the Soldier mountains. 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? Winds have created 1-2 foot fresh slabs in the upper elevations where more snow has fallen. You'll be most likely to find slabs near ridgelines and mid-slope terrain features like ribs and gullies. Slabs may extend down into middle-elevation terrain in areas where the wind has been blowing harder.

    How can you recognize it? Cracks shooting out from your skis or sled are an obvious sign of 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 1-2 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 are significantly changing from where we were last week. Slabs have been incrementally loading over the past nine days. Skier and rider-triggered avalanches and some early indicators from natural avalanche activity have slowly increased. Storm totals in the last 24 hours were most impressive in the Sawtooth and Western Smoky mountains and Banner Summit. Weather stations recorded 6-9 inches of new snow. Be prepared to encounter a different snowpack. 

In areas where the wind has been transporting this recent snow, wind slabs will be resting on layers of weak snow. Because of this weak snow underneath, these slabs may display more of a persistent slab character. What does this mean? It means they may be more sensitive and break wider and deeper than expected. As the slab over these weak layers gets thicker with more snow, the possibility of triggering avalanches in terrain sheltered from the wind comes to the table. In the past few days, we have seen a few small slabs that failed in largely sheltered terrain. These are clear indicators that encountering unstable slabs in sheltered terrain is becoming increasingly likely. 

The Avalanche Danger Scale is a tool to communicate the conditions you'll find in the backcountry. Each danger rating covers a broad range of conditions. The danger is MODERATE in the Soldier Mountains & Wood River Valley and Galena Summit & Eastern Mountain. However, we are at the upper end of that category. The further north and west you travel, the danger is CONSIDERABLE in the Sawtooth & Western Smoky Mountains and Banner Summit. These areas have seen more snowfall and crossed over the burly line of moderate danger into the more obvious realm of it being likely to trigger large avalanches in wind-affected terrain.

Today is not a good day to enter avalanche terrain lightly. Spend some time thinking about and looking at the snowpack you are encountering. It's a safe bet that you'll find weak layers in the upper snowpack and a patchwork of wind slabs resting on top. This week's human-triggered and natural avalanches are obvious signs that the snowpack isn't adjusting well to this new load. 

Regions covered