Avalanche forecast

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Avalanche danger

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

Wind events over the past week have blown the recent snowfall into slabs and drifts in upper elevation and alpine terrain. Avoid steep slopes where you find wind-drifted or pillowed snow. Slopes where you could trigger weak layers buried 4-6 feet deep are becoming few and far between, but it may remain possible on very steep, rocky, wind-affected slopes at upper elevations. 

Avalanche problems

  • Wind Slabs

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

    The wind events of the past week have finally ceased, but we'll continue to deal with the aftermath for a few more days. These strong winds produced a number of small to medium-sized natural and triggered wind slab avalanches across the forecast area.

    Fortunately, these wind slabs will be easy to identify. Watch for snow that is denser than snow found on wind-sheltered slopes and tell-tale clues such as surface texture and a pillowed, drifted appearance. In the alpine terrain of the Sawtooths, spindrift trickling down cliffs often forms slabs on the aprons below. Wind slabs will be less sensitive today, but I'd still avoid steep slopes where you find these indications of recent wind loading.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–3

    Triggering a 4-6 foot thick persistent slab avalanche is becoming increasingly unlikely. The weak layers we've struggled with all winter have not gone away, but they've become less reactive to the weight of a skier or rider. Due to their depth, they've also become very difficult to impact with your weight. Hard to trigger is not the same as impossible—you'll do well to keep them in mind and continue to factor them into your decision-making. It would take a dose of very bad luck, but it may be possible to trigger an unsurvivable avalanche in very steep (over 35 degrees), alpine terrain that is more likely to have thin spots where your weight may reach the weak layers.

    ADDITIONAL DISCUSSIONA combination of recent new snowfall and today's sunshine could produce small loose snow avalanches on steep, rocky slopes. Keep an eye on what's above you, and don't linger beneath steep terrain that's in the sun.

Avalanche Discussion

As we enter the first period of stable weather in quite some time, it's a good time to do a "State of the Union" on our current snowpack. 

The Soldier & Wood River Valley snowpack is the shallowest and weakest, especially in the mountains above Ketchum and Hailey. As is not uncommon in this area, there is plenty of weak, faceted snow—what's lacking is a slab of cohesive snow atop it. Unstable slopes are largely limited to where recent and/or past wind events have created dense or stiff snow in the upper pack. This was the case with a slide triggered during control work last week on Baldy. Storms earlier this winter favored the western half of this zone, and the snowpack there is more similar to Galena Summit.

The deepest snowpack exists in the Sawtooth & Western Smokys and Banner Summit zones. While these areas had thin snow at the start of the winter, they were heavily favored by the extended storm cycle at the start of the New Year. The early season weak layers are buried 4-6 feet deep, meaning that triggering an avalanche is difficult but likely unsurvivable. Avoiding thinner "trigger points" is the name of the game—these are more likely to be found in very steep, rocky, alpine terrain that is prevalent in the Sawtooths but less so in the Banner Summit area.

Finally, the Galena Summit & Eastern Mtns zone is the monkey in the middle. There is a great deal of variability across this zone, but it all falls somewhere between the two scenarios described above. The thin, windswept snowpack of the Boulder and Pioneer Mountains has characteristics of the Wood River Valley, where wind slabs sitting atop weak, faceted snow are the main concern. The Smoky Mtns of Galena Summit and the Baker Creek area have a bit deeper snowpack, with early-season weak layers buried 2-4 feet deep. In the White Clouds, the faceted snow near the ground seems especially pronounced—just a week ago, a monster broke over 500 feet wide and 4-6 feet thick.

So there you have it—the current State of the Snowpack. Just don't rip it in half...

Regions covered