Avalanche forecast

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Sawtooth Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

Triggering an avalanche large enough to bury a person is likely, especially in areas where wind has stiffened the snow surface or built thick drifts. Build in a wide safety margin. You could trigger avalanches remotely—from flat terrain below, above, and to the sides of steep slopes.

Avalanche problems

  • Persistent Slabs

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

    Triggering a large persistent slab avalanche is likely. Yesterday, we triggered small slabs at middle elevations near Cape Horn Summit. These slabs are thicker and easier to trigger in areas where you find drifts or a stiff snow surface.

    Various weak layers of snow (facets, crust-facet combinations, and possibly surface hoar) exist on most slopes. Ongoing storms stress these layers and increase the odds of triggering a persistent slab avalanche at all elevations. 

    You can avoid steep slopes and obviously wind-loaded terrain to reduce your chances of triggering an avalanche. Snowpack cracking, collapsing, or whumfing are clear signs of unstable conditions. Keep a close eye on your partner and the terrain above you. Persistent Slabs can release in surprising ways, break wider than expected, and release above or hundreds of feet away from where they are triggered.

    (12/21/2024) Skier-triggered avalanche near 9800' on a NE aspect in the northern Boulder Mtns.

  • Wind Slabs

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

    Your odds of triggering a large wind slab avalanche increase as you climb into windier terrain at upper elevations. Wind speeds may increase this afternoon, adding to yesterday's sensitive drifts. A triggered wind slab can potentially step down into the buried weak layers described in Problem #1 above. 

    Wind slabs often form near ridgelines or along steep mid-slope gullies. You can reduce your chances of triggering a wind slab by looking for and avoiding slopes with obvious signs of wind-loading, such as new cornice growth and large dunes or pillows of wind-blown snow.

Avalanche Discussion

It's Day 2 of a multi-day atmospheric river event bringing heavy snowfall to the region through Sunday. Yesterday's snow totals reached 6-10", and an additional 5-7" are expected today. The wind is forming new, sensitive drifts at upper elevations, and storm snow is adding to an already dense slab above various buried weak layers. Finding a safe place to play is becoming increasingly difficult. Avoiding obviously wind-loaded slopes is a good start. Still, the weight of storm snow adds significant stress to the fragile weak layers at middle and lower elevations, increasing your odds of triggering a slab avalanche on many steep slopes. 

As complexity increases, we have a narrowing margin for error. There is great skiing and riding to be had, but don't let your guard down. Several slopes are nearing their breaking point. The safest move is to keep your slope angles low and to stay out from under steep slopes.

Regions covered