Avalanche forecast

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Sawtooth Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 8 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

Your odds of triggering a slide increase as you climb through middle elevations on slopes that face away from the afternoon sun. Triggering a large avalanche is most likely in wind-affected terrain but remains possible in more sheltered areas.

A potent storm will cause the danger to spike tonight and Wednesday. Plan to be out of the mountains before dark.

Avalanche problems

  • Persistent Slabs

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

    Sunday, a skier triggered a 250 foot wide slab avalanche on a north facing, wind-loaded alpine slope in the Pioneer Mtns (photo 1, photo 2). You're most likely to trigger a similar, 1-3 foot thick avalanche where a dense slab rests above weak, faceted snow and crusts. Last week's extensive observed avalanche activity focused on N-NE-E-SE facing slopes at middle and upper elevations (near and above about 8500' in this zone). Many slopes in these areas have both thick slabs and suspect crust + facet combinations.

    You can use your boots, hands, or poles to quickly check for "old snow"—crusts and/or weak, grey, sugary facets—beneath a dense slab. Steep slopes with a > 1 foot thick slab above "old snow" are the most likely places to find trouble. While slabs are larger and more widespread in obviously wind-loaded terrain, triggering an avalanche is also possible on more sheltered slopes. 

    Cracks shooting out from you and "whumpfing" sounds as the snowpack collapses are red flags that indicate unstable conditions. If you experience these obvious signs of instability, avoid steep slopes with similar appearances, aspects, elevations, and snowpack depths. Unfortunately, you may or may not observe obvious signs of instability before triggering an avalanche. Avalanches could be wider than you'd expect, and you may be able to trigger them remotely—from gentler terrain above, below, or to the sides of steep slopes.

    Additional Discussion : Yesterday and last night's snowfall and wind did not signifcantly change the avalanche equation, but you may find fresh, thin wind slabs in exposed upper elevation terrain. The fresh slabs may have buried a new weak layer—facets, crusts and facets, or possibly surface hoar—and could be easy to trigger. The biggest threat these thin slabs will pose is triggering larger Persistent Slab avalanches as the small slides move downhill. 

    (12/11/2025) These large avalanches released between 8,500-8,900' on NE and E aspects near Copper Mountain.

Avalanche Discussion

Snowpack depths vary dramatically from drainage to drainage, as you climb in elevation, and as you change aspect (move to slopes that face different directions). Triggering avalanches is unlikely where the snowpack is less than about 1 foot deep. However, slope stability can quickly become questionable as you move into terrain with more snow.

Some slopes have adjusted to the load from last week's storm, but some slopes have not; we're in that transitional period where accurately determining whether individual slopes are safe or not is difficult. Given the uncertainty, picture the consequences of being caught in an avalanche before committing to skiing or riding steep slopes. Being carried through or into trees, rocks, or terrain traps is always bad, and our meager snowcover increases the chances of being injured in even small avalanches. 

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