Avalanche forecast

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Triggering a large, destructive avalanche is likely today. Layers of weak snow are buried beneath a thick, dense slab of snow. Avalanches may be triggered from long distances away from steeper slopes.

Avalanche problems

  • Persistent Slabs

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

    Two prominent layers of weak snow are buried underneath thick, dense slabs here:

    1. Near the base of the snowpack, you'll find a layer of crusts, facets, and spotty surface hoar. This layer produced numerous avalanches before the major storm and continued to do so throughout the storm. In this area, this layer is now buried 2.5 to 3.5 feet below the snow surface.
    2. The weak layer that last week's storm fell on was thinner but similarly weak. Many of the avalanches that occurred during the storm failed on this layer, often stepping down to the deeper weak layer described above. This upper layer is now buried 1.5-2 feet down.

    The weak layers are widespread, and so are the slabs overlying them. This means you can trigger large, dangerous avalanches on just about any steep slope you encounter, even at lower elevations and in terrain sheltered from the wind. A group of professionals traveling in the Sawtooths on Thursday reported unstable snowpack test scores in all of their pits and elected to avoid all avalanche terrain. Ethan and I were in the Headwaters of the Salmon River the same day and we experienced large, booming collapses that shook the snow off of trees up to 1000' away (video). Tilt these collapses up onto a steeper slope and you have yourself an avalanche.

    Persistent weak layers produce avalanches that behave in surprising ways. They can break wider than you'd expect and can be triggered remotely—from gentler terrain above, below, and to the sides of steep slopes. Plan your day expecting to be able to trigger these types of avalanches. Thanks to the widespread nature of the weak layer+slab combination, avoiding slopes steep enough to slide is the only way to ensure a safe return home. Playing on or below steep terrain continues to be a risky dice roll.

    ADDITIONAL DISCUSSION: Wind speeds increased for about 6 hours last night before calming back down. There is plenty of snow to move around and some slabs likely formed in exposed terrain. Though relatively thin, I expect these to be touchy. The wind will pick up again this afternoon and another round of slabs will be forming. Triggering one of these slabs can make for an effective trigger for avalanches failing on deeper weak layers. 

    (12/14/2022) This very large avalanche released on the SW-face of Savier Pk in the northern Smoky Mountains.

Avalanche Discussion

The intense storm that blanketed our area drew to a close 5 days ago. This snow fell on an exceptionally weak snowpack that developed during early-season droughts. The resulting avalanche cycle was truly impressive. Hundreds of large avalanches occurred, on slopes from the valley floors all the way to the mountaintops. Houses were hit, the Big Wood River was dammed by avalanche debris, and multiple human-triggered avalanches occurred. It's hard to drive around or ride through the mountains and not see the aftermath of an avalanche.

The snowpack has been getting a much-needed break the past few days, allowing the healing process to begin. Unfortunately, this is not a fast process. Thanks to the whims of physics and the properties of water, weak layers form far more quickly than they heal. I'm optimistic that we can put these weak layers behind us, but I'm confident that we haven't done that yet.

I wouldn't be an honest man if I told you that waiting for stability to improve is easy. Standing in the sun and looking at steep slopes covered in perfect powder and deciding not to ski or ride them is flat-out hard. Trust me, I know. Nothing brings me more joy than playing in steep terrain on snow-covered mountains. But that's not where you will find me this weekend. The chance of triggering large, destructive avalanches is far too great. Instead, I'll be searching out low-angle ridgelines for skiing and deep, powdery meadows for riding, all while paying close attention to the terrain above me. I strongly encourage you to do the same. We are all lucky that this region provides plenty of opportunities for both. 

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