Bollettino valanghe

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

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2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

Wednesday, riders triggered avalanches where the wind formed drifts and stiffened the snow surface. Similar triggered avalanches are possible today. The fresh slabs are largest and most widespread in upper-elevation terrain and in bowls below steep cliff bands, but you could also encounter them at middle elevations. Expect numerous small loose snow avalanches on slopes that face the sun. 

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Recent snowfall and shifting wind has formed fresh wind slabs in exposed terrain. Wednesday, snowmobilers triggered small wind slab avalanches in the southern Sawtooths. One rider was caught and carried but was unharmed (report). In the Smoky Mountains near Titus Peak, skiers remote triggered a large avalanche from a low angle ridgeline (report). Over the past week, multiple large natural avalanches released in wind-loaded upper elevation terrain of the Sawtooths and Smokys (photo above/right, list). 

    Wind slabs formed atop a variety of weak snow layers, including facets on shadier slopes and facets or crusts on sunnier W-SW-S-SE aspects. Smaller wind slabs on sunnier slopes have shown the potential to step down to deeper buried weak layers resulting in very large, destructive slides (report). Light to moderate wind and ongoing light snowfall has made wind-loaded slopes hard to identify. Look carefully for drifts and pillows of snow below exposed ridgelines, on the sides of gullies or chutes, and near large terrain features. In the Sawtooth Mtns, you could find slabs below large cliff bands and on the aprons of chutes and couloirs. While more prevalent at upper elevations, some slabs may exist on windier middle elevation slopes. Snowpack collapsing or cracks shooting out from your skis or sled are obvious signs of instability. 

     

     

    (2/22/2023) This very large avalanche released at about 10,000' on a N face of Merritt Pk in the Sawtooths.

Avalanche Discussion

Steering clear of recently formed drifts and slabs is the most effective way to stay out of trouble. Recently wind-drifted snow may not be obvious as signs of recent wind affect are cloaked with low density snow. While fairly minor, there is one other scenario to keep in mind as you prepare to head into the mountains:

  • Loose Snow Avalanches: Up to a foot of snow has fallen here since Sunday. This recent low-density snow sits atop extremely weak facets on some NW-N-NE-E facing slopes. On very steep slopes approaching 40 degrees, it won't take much to get surficial sluffs moving (photo). Today will be mostly clear. Direct sunshine will trigger numerous natural loose snow avalanches. These probably won't be big enough to bury you, but they can pack a punch and could knock you over, pushing you where you don't want to go. Sluffs have the potential to trigger wind slab avalanches when recent winds formed stiff drifts lower in cirques and on the aprons of chutes and couloirs. 

Pay attention to the terrain above you. Remember that even small avalanches can have bad outcomes in complex terrain. Before committing to skiing or riding a slope, think about where an avalanche could carry you. Could you get pushed over cliffs, through trees, or into creeks or gullies? Slopes with these terrain traps are inherently more dangerous than open slopes with a clean runout.

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