Lawinenlagebericht

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

Watch for pockets of wind-drifted snow in upper elevation terrain. Wet snow avalanches are possible. If you're sinking into a mushy snowpack, stick to gentler slopes and don't linger under large, steep, rocky terrain.

 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Yesterday, I observed a few small wind slabs in the central and southern Sawtooths (photo at right and below). Some of these slabs occurred very near ridgelines and some released on aprons and below cliff bands where recent snow "spin-drifted" into thicker slabs. Despite the heatwave, we observed active wind-loading again yesterday in the alpine. 

    If the snow suddenly gets deeper and/or stiffer, you've found a wind slab. If you see cracks shooting out from your skis or boards, think about the consequences of being knocked over by a small avalanche before committing to skiing or riding the slope.  

    ADDITIONAL DISCUSSIONSome slabs may have formed over weak snow that developed during the drought of January and early February. This slide (report) in the Smoky Mountains illustrates what's possible in isolated areas with ideal wind-loading and a well-preserved weak layer. This problem is not widespread, but worth keeping on your radar. 

    (3/2/2022) This small wind slab avalanche released just below an upper elevation ridgeline near McDonald Pk. The slab entrained wetter snow as it moved down slope.

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    We've observed countless wet loose avalanches in the last couple of days. Most of these occurred at middle and lower elevations during bouts of rain on Tuesday. Yesterday in the Sawtooths, I watched as the sun triggered small avalanches on very steep, rocky, upper elevation slopes. Rain and yesterday's sun released most of the "easy pickings".  I'd expect less natural avalanche activity today, but very warm temperatures and periods of hot sun will keep this problem on the table. 

    Last night was the third night with a weak or nonexistent overnight freeze. It won't take long for thin surface crusts to break down and under them, it's still a soupy mess. Today, avalanches are most likely at low elevations and on very steep slopes that face the sun. Most of these slides begin near rocks or where the snowpack is less than about 2' thick. 

    If you're sinking into slush, it's time to find gentler terrain or cooler slopes to ride. Although I'd expect most of these slides to be relatively small, it's not a good day to linger under steep slopes. Avoid low elevation terrain traps, like creek/river bottoms and gullies, especially in the afternoon. 

    (3/2/2022) Numerous small wet loose avalanches in the southern Sawtooths near McDonald Peak.

Avalanche Discussion

Weak snow developed at the surface during the drought of January and February. Small storms clipped the northern end of the forecast area, favoring the Banner Summit Zone. Tuesday's storm brought an additional 7-10" of dense snow to Banner Summit above about 8,000' capping off a slab that's anywhere from 1-1.5' thick. This last storm proved to be just enough to tip the scales, producing multiple slab avalanches near Bull Trout Point (observation). 

South of Banner is a different story. It's snowed less, and the slab is thinner. Only a handful of slab avalanches were observed in the Sawtooths, most of which were small wind slabs (photo). This doesn't mean the weak layer in these zones is absent. Yesterday in the northern Boulders, Chris found unstable snowpack test scores, and observed cracking in ~1' drifts (observation). These drifts sat on the similar weak layers that formed during the drought. The difference here, as well as other areas outside of Banner Summit, is that these conditions are more infrequent and require some wind-loading to build the slab. 

Yesterday, I spotted this large persistent slab avalanche on the N. face of Saviers Pk in the Smoky Mountains. While an apparent outlier, it's an indication that this problem lurks in isolated areas with ideal wind-loading and a well-preserved weak layer. You're not likely to find many locations that can produce this large of a slide, but the possibility is there. This avalanche and the ones near Banner Summit may foreshadow what's to come if large-scale snow returns to the forecast area.

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