Bollettino valanghe

Sawtooth & Western Smoky Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

Sat
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You're likely to trigger avalanches large enough to bury a person. Slides are most likely in windy, alpine terrain and on middle elevation slopes facing away from the sun. Avalanches may break wider than expected and can be triggered remotely—from gentler terrain above, below, or to the sides of steep slopes.

Problemi valanghivi

  • Wind Slabs

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

    Recent snowfall and variable SW-W-NW wind built fresh drifts that may be sensitive to your weight. These slabs will be thicker and more abundant as you climb into the alpine, where snow totals are greatest and the wind is strongest. Look for and avoid fresh dunes, drifts, and pillows that are commonly found near ridgelines and the sides of cross-loaded gullies. Cracking in stiff drifts (photo at right/below) indicates that you've found a sensitive slab. 

    (12/4/2023) Cracking in stiff drifts is a clear sign that the snowpack is unstable. This would have been an avalanche in steeper terrain. Galena Peak, Boulders.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1.5–2

    You're likely to trigger a persistent slab avalanche large enough to bury you. A layer of weak snow underlies a 2-3 foot thick slab on many upper elevation slopes and middle elevation slopes that face away from the sun. Recent snowfall and drifting snow added stress to this weak layer in both wind-loaded and sheltered terrain. 

    Direct feedback, like cracking or collapsing of the snowpack, indicates that conditions are dangerous. You may even trigger avalanches remotely, from gentle, low-angle terrain as you ascend a safe ridge (video). Without these obvious clues of instability, you can quickly and easily identify this layer by digging a quick hole. The weak facets will appear grey and feel loose and crumbly. On middle elevation slopes that face away from the sun, they may rest atop a stout ice crust, a particularly alarming and weak structure. The only surefire way to avoid this problem is to steer clear of steep slopes where these old facets exist. 

    (12/4/2023) This large avalanche was observed at 10,000' on the E/NE face of Eureka Peak above the Alturas Lake Creek drainage.

Avalanche Discussion

A series of storms brought 1-1.5' of snow to this zone in the last 36-hours. While storm totals are not overwhelming, the load is significant, especially considering the generally weak, shallow snowpack it's adding to. While no significant accumulations are expected today, NW wind will continue to build slabs in exposed terrain.

Where the snowpack is thin, you'll find little to no avalanche hazard, but real-deal avalanche problems can arise quickly as you climb into windier terrain and as you wrap around to shadier slopes where the weak layers are at their worst. Today's a great day to keep it simple. The season is young, the snowpack is shallow, observations are limited, and we have a lot to learn. What we do know, is that the snowpack is generally weak where decent skiing exists, and it's shown its ability to produce large avalanches (video). I recommend that you keep your terrain choices conservative today, keep your slope angles low, and be alert to overhead hazard.

Regioni coperte