Avalanche forecast

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Avalanche danger

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

You could trigger a 1.5-2 foot thick avalanche in shady, wind-sheltered terrain. In more exposed locations, you could trigger hard or soft drifts or slabs that formed over the past several days. Consider the consequence of a slide before committing to avalanche terrain. Even small slides can have bad outcomes on slopes with cliffs, trees, and terrain traps.

Avalanche problems

  • Wind Slabs

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

    Last weekend's snow and northerly wind formed soft 1-2' thick slabs in exposed terrain. A handful of small natural wind slab avalanches occurred over the weekend (Galena Pass, Banner). Monday, we spotted a large wind slab in the Soldier Mtns (photo). 

    This problem is most pronounced at upper elevations where slabs are larger and more widespread. Look for them near ridgelines, on the sides of gullies and chutes, and near prominent terrain features. In the steep, rocky terrain of the Sawtooths, you'll also find slabs where snow has cascaded down and accumulated below cliffs (example).

    Cracks shooting out from your skis or sled are an obvious sign of instability (example). Watch for drifts, dunes, and ripples on the snow surface. Older hard 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 closer to the surface.

    (1/29/2023) This small wind slab released naturally on Titus Ridge near Galena Summit. It failed on a E/NE-facing slope at 9,600'.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2

    Since mid-January, skiers and riders have triggered several avalanches involving a layer of surface hoar buried 1.5-2 feet deep. A skier triggered a slide on this layer last weekend near Galena Pass (view report). The surface hoar "problem" is stabilizing, but it remains capable of producing avalanches on some slopes steeper than about 35 degrees. 

    Buried surface hoar is challenging to deal with. Its patchy distribution means you may find it on one slope but not the next, and it can be hard to identify when searching for it in a snowpit (see photo to right/above). It's often best preserved and more sensitive in small clearings and open, wind-protected terrain on shadier aspects. 

    You can effectively reduce your risk by avoiding slopes facing NW-N-NE that are steeper than about 35 degrees. Consider the consequences of going for a ride. Even small slides can have bad outcomes if they lead to trees, cliffs, or a creek bed. 

    ADDITIONAL DISCUSSION: Older weak layers (often facets found near crusts, with some surface hoar) exist deeper in the snowpack. These layers are buried beneath dense, 3-4+ thick slabs. While triggering them is unlikely, it can't be ruled out in steep, rocky, wind-affected terrain. 

    A skier triggered this 1-2 foot thick avalanche on Sunday Jan 29th on a N-NE aspect at 9100' near Titus Ridge. It failed on a layer of buried surface hoar.

Avalanche Discussion

Here's a quick top-down overview of the snowpack and associated avalanche concerns:

Upper Snowpack

  • A few generations of wind slabs formed in the past week. The most recently formed slabs are small and softer but may be more reactive to your weight. Warm mountain-top temperatures have helped this problem heal, but I'd keep it on your radar if you plan to ski or ride wind-exposed terrain. Triggered wind slabs can be effective triggers for deeper weak layers in the snowpack.
  • The persistent weak layer (facets or surface hoar) buried in early January lies beneath a 1.5-2 foot thick slab. Its shallow depth means impacting it remains a very real possibility. I found this layer in all of the pits I dug in the Banner Summit Zone Wednesday near Cape Horn Summit (observation). Ski guides also found this layer in the central Sawtooths on Tuesday. Although present, snowpack tests indicate that this layer is stabilizing. While the odds are low, I'm not ready to ignore the chance of triggering a slide on wind-protected, shaded slopes where this layer is at its worst.

Middle and Lower Snowpack

  • Snow depths in a large portion of this zone exceed 5 feet. Weak layers that were buried in November and December lie beneath very dense, heavy slabs of snow. Impacting these weak layers is unlikely but not impossible.

The consequences of triggering avalanches can vary significantly. Triggering a small slide in terrain free of rocks, trees, and terrain traps is much less dangerous than triggering a slide in extreme, rocky, treed terrain with a terrain trap at the bottom. Think about the consequences of being caught in a slide before committing to skiing or riding in sizeable avalanche paths. 

 In case you missed it, check out the latest Weekend Update here.

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