Avalanche forecast

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
View on map

Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Recent snowfall and windblown snow are slowly adding weight to a very weak snowpack. Triggering an avalanche 10-14 inches thick is possible on wind-exposed, upper elevation slopes—especially those that are getting drifted by yesterday and today's wind. Decrease your risk by avoiding steep, wind-affected slopes.

Avalanche problems

  • Persistent Slabs

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

    Recent snowfall has formed a soft, 6-10" thick slab atop extremely weak, faceted snow that formed during the 3+ week dry spell since mid-November. Even this small load produced several small avalanches during and right after the most recent storm. While our weak layer is "something special", we still haven't added enough slab to produce widespread instability. In our northern zones where more recent snow accumulated, the snowpack is even closer to the brink. The last storm produced avalanches large enough to bury people in the Western Smokys, Sawtooths, and Banner Summit area. 

    Yesterday's wind was visibly transporting snow along higher ridgelines and in alpine terrain. This wind is helping to add the piece of the puzzle that's mostly missing on sheltered slopes—a thicker and denser slab on the facet layer. A small natural avalanche in wind-exposed terrain was observed yesterday in Baker Creek, and skiers in Owl Creek were able to release a small slide with a ski cut.

    You can greatly decrease your chances of releasing a slide by avoiding slopes with evidence of recent wind effect—especially in the Soldiers Mountains that have received more recent snowfall and wind. Triggering an avalanche on wind-sheltered slopes is unlikely, but use extra caution on steep slopes and convexities approaching 40 degrees.

    (12/17/2020) Small avalanche that ran on the faceted old snow surface in the Soldier Mountains.

Avalanche Discussion

Drip. Drip. Drip. A trickle of loading from snowfall and, more recently, wind is ever so slowly loading the very weak facet layer that formed during the prolonged dry spell. Before snowfall buried the weak layer on December 11th, we had a faceted snow surface that was fairly uniform across the forecast area. This uniformity is beginning to break down as different portions of our forecast area get loaded at varying rates. While we're only talking differences in inches of snowfall here, with a facet layer as weak as ours, that can make all the difference.

Although the variation across our forecast area is more of a spectrum, it's usually helpful to simplify matters. So far, none of our area has received a sufficient load to produce widespread instability on the facet layer. But our northern zones (Sawtooths & Western Smokys, Banner Summit) received more recent snowfall, and as a result, have been closer to the brink. The last storm produced more widespread, and larger, avalanches in these zones.

The trend of a diverging pattern between our northern and southern zones will continue with today's weather system strongly favoring the north. It seems likely the Sawtooths & Western Smokys and Banner Summit zones will finally reach the tipping point at some point tonight or tomorrow. Watching what happens in these zones will likely foreshadow conditions in our southern zones once they catch up.

Regions covered