Bollettino valanghe

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

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

In sintesi

Your main avalanche concerns involve the new snow from the past week. Be on the lookout for sensitive pockets of wind-drifted snow near ridgelines; cracking in these drifts is an indication of instability. Small loose snow avalanches will be easy to trigger on very steep slopes, particularly where the sun is melting the snow surface. Triggering large avalanches that fail on deeper weak layers is most likely in very steep, rocky, alpine terrain.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Be on the lookout for freshly formed wind slabs in your travels today. Surface textures like dunes and drifts indicate the wind has been at work. If the snow you are moving through quickly becomes deeper, stiffer, and more dense, you have found a wind slab. Cracks shooting out from your skis or machine are a clear sign that the slab you found is not well bonded.

    Look for these slabs near terrain features that slow the wind down and force it to drop the snow it is transporting. Typical locations are near ridgelines and along the sides of mid-slope gullies. Slabs will be at their largest, most reactive, and most dangerous in upper elevation terrain. Even small slabs can knock you off your feet and send you for a nasty ride if you encounter them in ugly terrain. Consider the consequences of an unplanned, high-speed trip down the slope you are playing on. 

    ADDITIONAL DISCUSSION: Loose snow avalanches involving the recent snow will be small but may be easy to trigger on steep slopes. These will run quickly downslope on the stiff surfaces underneath. As periods of bright spring sunshine melt the new snow, these loose snow slides will take on a moist/wet character. 

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–2.5

    Weak layers buried under dense slabs in the upper few feet of the snowpack have had some time to rest, but they haven't gone away. The consequences of triggering an avalanche involving this weak snow would be severe. If you dig down, you'll find facets and bands of surface hoar on shaded slopes and icy crusts with associated facets on slopes that face the sun. 

    Your first sign of instability involving these weak layers would be the large avalanche you trigger. If triggered, these slides may break well above you on the slope and fail widely. You can drastically reduce your risk of encountering a slide like this by steering clear of very steep, rocky, heavily wind-affected terrain. 

Avalanche Discussion

Your primary avalanche concerns today involve the 5-15 inches of snow that fell over the past week. Roughly half of this fell last weekend, with the other half falling on Thursday. Stiff, icy crusts underlie this recent snow on slopes that tilt towards the sun. Expect to find some relatively small wind slabs that remain sensitive to your weight today. Most of these slabs aren't likely to be large enough to bury you, the main hazard they present will be if they knock you off your feet or machine in unfriendly terrain.

Triggering very large avalanches that fail on deeper weak layers is more likely in this zone than in any of our other forecast zones. These mountains are high and cold and the snowpack is thin so the weak layers tend to linger here for a long time. The windswept, alpine nature of the terrain here means that there are plenty of thin spots in the slabs on top of these weak layers, which makes impacting them with your weight easier. It would take a dose of bad luck to trigger one of these beasts, but you would need an equal dose of good luck to survive the experience. Triggering these slides is most likely in very steep, rocky, wind-swept alpine terrain. 

As the danger gradually decreases, many of us find ourselves drawn towards bigger, steeper, more complex terrain. When we head into this terrain, we enter a dangerous environment. Catching an edge, crossing your ski tips, or losing control of your machine on a steep, firm slope can all have severe consequences. This is also the type of terrain where you are most likely to trigger a slide that can knock you off your feet or a slide that can wipe out the season's snowpack. If this is the type of terrain you are headed for today, remember to keep things tight. Travel one at a time, keep your eyes on your partners, and make a plan for how to move safely through the terrain. Respect the environment you are traveling through and remember that avalanches are only one of the hazards posed by the mountains.  

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