Avalanche forecast

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Triggering a dangerous avalanche is likely. Skiers and riders triggered numerous avalanches over the past week—most from low-angle terrain a large distance from where the avalanche released. Avalanches will be larger and more destructive as you gain elevation and move into wind-affected terrain. Traveling safely even near avalanche terrain is difficult—build in extra safety margins.

Avalanche problems

  • Persistent Slabs

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

    Expect to trigger a 1-2.5 foot thick Persistent Slab avalanche in areas sheltered from the wind. As you climb into windier terrain you could trigger a slide up to 5 feet thick. These avalanches will break wide and may fail in unusual locations. Anticipate remotely triggering these avalanches a large distance away from where they release.

    We've observed dozens of Persistent Slab avalanches over the past week—many of which were human-triggered. Assume this problem exists on all upper and middle elevation slopes and shadier aspects at low elevations. Avalanches are failing on a variety of weak layers; surface hoar and/or facets on shaded slopes and a crust + facet combination on sunnier slopes. 

    The avalanches described above could "step down" to an additional weak layer of snow near the ground. This basal weak layer exists on upper elevation slopes and shaded middle elevation slopes. Avalanches that break down into this snow are likely to be unsurvivable (video).

    (1/19/2024) This photo shows several large avalanches that were remotely-triggered by riders in the Beaver Creek drainage. The furthest away slide is over 800 feet wide, and failed a half mile from where the avalanches were triggered, out of sight on the right side of the photo.

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Ongoing light snowfall will keep the possibility of smaller avalanches on the table. Look for fresh cornices or small wind slabs in areas exposed to the wind. Loose snow avalanches are possible on slopes sheltered from the wind. These problems may be large enough to knock you off your feet or bury you in a terrain trap. More concerning is the possibility for these slides to trigger the Persistent Slabs described above.

Avalanche Discussion

Yesterday, I expected to trigger an avalanche. I mean, why not? Numerous, large human-triggered avalanches have been reported over the last week. The frequent collapsing of the snowpack is a reminder that January's storms stacked dense slabs atop an ugly weak layer. A weak layer that is uniquely widespread. A weak layer that's produced avalanches breaking thousands of feet wide. A weak layer that's enabled slides to pull back into relatively flat terrain above steeper slopes. Simply put, it's dangerous out there. 

What worries me most is that the skiing and riding are great! Small storms continue to roll through with minimal wind. Most snow surfaces are soft and inviting. Yesterday, I caught myself eyeing up a steeper exit than I'd planned. Snapping back from my brief lapse of powder-lust I reminded myself of the continual collapses, the ugly snowpack structure, and the unstable test scores—no thanks. Although small, the line I imagined traversed above creek beds and ended in a road cut. These not-so-obvious avalanche paths at lower and middle elevations are deceptively hazardous.

Ongoing storms have not given our Persistent Slab problem a break. Enter the mountains with a conservative travel plan and stick to it. Be aware of people near, above, or below you;  accidentally triggering a large avalanche on another group is a real possibility.

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