Avalanche forecast

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Avalanches large enough to bury you are most likely where the wind has formed drifts or stiffened the snow surface. Avalanches are less likely in areas sheltered from the wind. You could trigger slides remotely—from flat terrain below, above, and to the sides of steep slopes.

Avalanche problems

  • Persistent Slabs

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

    You could trigger 1.5-4 foot thick slabs, especially where wind formed drifts or stiffened the snow surface. Triggering an avalanche is less likely—but not out of the question—on steep slopes that are completely sheltered from the wind. The slabs rest above a variety of weak layers (facets, surface hoar, and crusts + facet combinations). The widespread nature of these weak layers means avalanches are likely on many aspects. 

    Snowpack cracking and collapsing or whumpfing are clear signs of unstable conditions. However, a lack of these obvious warning signs doesn't mean you're in the clear. Approach the mountains with the assumption that weak layers exist on many slopes. 

    Avoiding steep, wind-loaded slopes can significantly reduce your chances of triggering an avalanche. Persistent Slabs can release in surprising ways, break wider than expected, and release above or hundreds of feet away from where they are triggered. It's possible to remotely trigger an avalanche from flat terrain near steep slopes. Manage your group by riding or crossing steep slopes one at a time, and avoid areas where terrain features like gullies, cliffs, or dense trees could increase the consequences of a slide.

     

    (12/30/2024) This avalanche, in the headwaters of Cabin Ck, likely happened near the end of the recent storm. The avalanche stepped down to mid-December weak layers. Photo: Sawtooth Avalanche Center

  • Wind Slabs

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

    You may be able to trigger wind slab avalanches that formed near ridgelines and in cross-loaded areas on the sides of gullies. The size and chance of triggering these slides increase significantly as you climb into windier, alpine terrain at upper elevations. These avalanches could step down to the buried weak layers described above. Watch for snow pillows, dunes, and ripples, and feel for stiff snow under your feet or sled. These are signs the wind has been at work transporting snow.

Avalanche Discussion

The snowpack will slowly adjust to the weight applied by the post-Christmas loading event. This process takes time and is slowed by ongoing snowfall and wind-loading. A recap since Sunday:

  • So far, we've recorded ~100 avalanches focused around preferentially wind-loaded NE and E aspects between 9,000-10,000' (view rose).
  • Twelve significant human-triggered avalanches were reported (view rose). Three of these were triggered Tuesday by skiers near Titus Lake.
  • Nearly all of the 50+ recent observations we've received report obvious signs of instability, such as avalanches, cracking, or collapsing. 

Yesterday's snowfall favored the western slope of the Sawtooths and the western Smokys, including the mountains above Smiley Ck. Winds blew at loading speeds from the WSW-W-WNW. Look for fresh wind slabs near ridge tops, steep cliff faces, and chutes. These slabs may be dangerous in their own right and could trigger much larger, more hazardous, Persistent Slab avalanches. 

There's great riding and skiing to be had, but we're still cautious about entering or traveling below avalanche terrain. Keep a close eye on your partner and the terrain that's above you.

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