Avalanche forecast

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Sawtooth Avalanche Center
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Avalanche danger

Mon
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

Expect many large avalanches to release on their own. Avalanches may hit roadways, trails, and structures in the valley bottoms. Stay off of and out from under steep slopes. You may be able to trigger avalanches remotely — from flat terrain below, above, and to the sides of steep slopes.

The backcountry Avalanche WARNING does not apply to the HWY 21 avalanche program.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Certain
    Size
    1.5–3

    Large destructive avalanches are near certain today. Stay off of, out from beneath, and away from the edges of steep slopes. Avalanches could break hundreds of feet wide and run long distances.

    Conditions are most dangerous where wind blown snow forms thick, stiff slabs. Feet of recent snowfall makes avalanches possible in sheltered terrain as well. The buried weak layers (sugary facets, surface hoar, and crusts) may reach their breaking point today. 

    Cracking, collapsing, and whumpfing are bullseye information for unstable conditions. Persistent Slabs can release in surprising ways, break wider than expected, and release hundreds of feet away from where they are triggered. Avoid avalanche terrain; this includes gentler terrain below steep slopes.

    (12/27/2024) Large natural avalanche in Castle Creek that broke an estimated 4 feet thick on 12/26.

    Photo: Sun Valley Guides

  • Storm Slabs

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

    Avalanches large enough to bury people are very likely today on all aspects and elevations. Heavy snowfall (or rain at lower elevations), wind-blown snow, and increasing temperatures will combine to create widespread, reactive storm slab avalanches. These slabs may fail naturally and should be easy to trigger on steep slopes.

    Storm slabs will be thicker, stiffer, and more dangerous in windier terrain. Rain can rapidly increase the threat of these avalanches. Any storm slab that releases could "step-down" into more deeply buried weak layers, causing an even bigger avalanche (see Persistent Slab problem).

    (12/28/2024) This avalanche was triggered along a wind-loaded ridgeline and is representative of the storm slab problem expected today.

Avalanche Discussion

Today is a day to avoid all avalanche terrain. Exceedingly dangerous avalanche conditions are widespread throughout most of the forecast area as the multi-day storm intensifies. Expect the size and frequency of avalanches, or danger, to steadily increase today and peak this afternoon.

We expect many types of avalanches to release today: persistent slabs, wind slabs, storm slabs, dry loose, and wet loose. Whatever the flavor of avalanche, two points stand out:

  1. They will be big enough to bury or kill people.
  2. Many will release naturally, on their own. 

There is plenty of excellent riding on low-angled slopes not connected to steeper terrain above. Remember that stepping out of bounds at a ski area or out of your car for a rip is stepping into HIGH danger. Natural and human-triggered avalanches may run long distances and can impact gentler terrain below. We’re still in the midst of a big storm with a large avalanche cycle likely occurring but obscured by poor visibility.

Regions covered