Avalanche forecast

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Avalanche danger

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

Large avalanches are unlikely, but triggering smaller wind drifts and slabs remains possible in upper elevation and alpine terrain. On very steep slopes facing the sun, wet snow avalanches will become likely as the day heats up.

Avalanche problems

  • Wind Slabs

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

    Thursday's spring storm produced a combination of new snow and wind, and numerous natural and triggered wind slabs were reported across the forecast area on Friday. Most of these were fairly small, but at least one (Gladiator Peak) was large enough to bury a person. Yesterday in the Sawtooths, Ben observed a fresh round of wind loading—and most stations reported an uptick in wind last night.

    Many of these wind slabs formed on weak surfaces, including slick crusts, facets, or some combination of these. Wind slabs could remain touchy today, especially with the possibility of additional wind loading last night. Being able to identify and avoid wind slabs is a critical backcountry skill—read more in the Forecast Discussion below. Long story short, identify and avoid.  Wind slabs often looked rippled or "chalky", and usually have a dense, punchy, or hollow feel. Once you identify a wind slab, the best approach is to avoid the problem by giving the loaded area a wide berth.

    (3/26/2021) Professional observers in the southern Sawtooths found touchier than expected wind slabs on Friday, and chose to bail on their objective.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1

    Natural wet loose avalanche activity increased with yesterday's sunny skies and warming temperatures (photo above/right). While yesterday's heat may have caused most of the easy pickin's to run, there are still plenty of sunny slopes that could slide today. With warmer temperatures last night and hotter weather on tap today, expect the likelihood of natural and triggered wet slides to increase quickly this morning.

    As sunny slopes heat up, monitor the mushiness of the surface. Once the mush gets deeper than about 4-6", triggering a sizeable sluff of wet snow on slopes approaching 40 degrees will become likely. Plan to be off of steep, sunny slopes early in the day, and don't linger beneath terrain that is getting direct sunshine. Wet snow avalanches should be relatively small, but as meltwater percolates a bit deeper today we may start to see a few that are larger and more dangerous.

    (3/27/2021) The past two days of sunshine and warming temps produced numerous wet loose avalanches in the northern Sawtooths. Most originated from cliffs on a SE-facing slope.

Avalanche Discussion

Wind slab problems are different in that they tend to be localized in the terrain. In contrast to a buried weak layer or a uniform blanket of new snowfall, wind slabs often occur in specific locations with (sometimes) identifiable boundaries. Being able to manage a wind slab problem is a critical backcountry skill—this is especially true for skiers and riders who seek out steeper terrain in alpine environments. While wind slabs can—and do—exist anywhere there is snow on the ground, their preferred habitat is the complex, wind-exposed, open terrain of the high mountains. Let's go over the identification, "evaluation", and avoidance of wind slabs.

IDENTIFICATIONIdentifying wind slabs does not involve getting out your shovel. You find them primarily by looking and feeling. Look for changes in surface texture. Wind slabs often looked rippled or "chalky". Feel for differences in snow consistency. Drifted areas usually have a dense, punchy, or hollow feel. Snow that has visual effects from wind isn't always a wind slab, which is why a combination of looking and feeling is so important. This can take some experience, so be extra-cautious until you build your skills.

EVALUATIONI almost skipped adding this section because evaluating wind slabs can be a slippery slope (pun intended), and it's almost always best to skip straight to avoidance. The sensitivity of wind slabs can be tough to predict and often changes from location to location. Stomping or slope cutting a wind slab on a low-consequence slope can provide useful information, but not getting a result is no guarantee that the next loaded area won't provide a magic carpet ride. 

AVOIDANCEAs I alluded to above, once you've identified a wind slab, the best approach is usually to let sleeping dogs lie. Avalanche professionals rarely feel comfortable sliding or riding on a wind slab—even if there has been no sign of instability. If you're able to identify the perimeter of a wind slab, then you can navigate around it—giving it a wide berth and yourself a healthy margin of safety. If the boundaries of the wind slab aren't clear, then avoiding the slope entirely will be the best option.

Be sure to catch up on what happened this past week in Scott's Weekend Update!

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