Bollettino valanghe

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

Fri
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

Avalanche conditions are dangerous. Today's storm will form sensitive slabs of wind drifted snow at upper elevations. Much larger, 2-4 foot thick avalanches are possible on some slopes. Unfortunately, figuring out exactly which slopes are dangerous is almost impossible. You may be able to trigger avalanches remotely—from gentler terrain above, below, and to the sides of steep slopes. Choose simple, lower-angled terrain to reduce your risk.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    You could trigger a 2-4' thick persistent slab avalanche on buried weak layers (sugary facets or crust + facet combinations). This problem is worst on middle and upper elevation slopes facing W-NW-N-NE-E-SE. 

    Unfortunately, unstable slopes probably won't provide obvious signs of instability, like snowpack collapsing or cracks shooting out in front of you. Snowpack stability tests are likely to be inconclusive and are of limited use. Tracks on a slope don't mean it's safe. Avalanches can be triggered by the second, third, or fourth rider on a slope. In low probability/high consequence situations like this, there's a good chance the first sign of instability you'll see is the avalanche you trigger.

    The likelihood of triggering a slide is decreasing, but the thick, dense slab makes the consequences severe. Persistent weak layers can fail unpredictably and break wider and higher on slopes than you might expect. Avoiding avalanche terrain is the only surefire way to manage this problem. Short of that, you can reduce your risk by avoiding large avalanche paths and those with ugly consequences if you are caught in a slide.

  • Wind Slabs

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

    Expect to encounter freshly formed, sensitive wind slabs in terrain exposed to the wind. These slabs will grow in size and extent as the storm intensifies this afternoon. Look for smooth pillows of windblown snow near ridgelines, mid-slope gullies, and in cirques below large cliff bands. Cracks shooting from your skis or sled are a clear sign that you've found an unstable slab. These smaller avalanches can serve as an effective trigger for the much larger and more dangerous persistent slab problem described above. 

    ADDITIONAL DISCUSSION: Loose snow avalanches are possible during periods of intense snowfall. They may also occur during brief periods of sunshine, especially in very steep, rocky terrain.

Avalanche Discussion

Today's avalanche conditions are both tricky and dangerous. Wind slabs at upper elevation may become an issue this afternoon, particularly in the Soldier Mountains which are expected to receive the most snow. These slabs may be the most obvious problem today, but they should be easy to identify and avoid. Persistent slabs, on the other hand, are the trickier and more dangerous avalanche problem, the one that should dictate the type of terrain we choose to ride. Watch Ben's video from Baker Creek to get a quick sense of this problem (video). This video shows the general setup that we're looking at across the forecast area; a dense slab of snow sits atop weak layers that were formed and buried in February.

Our last major storm ended over a week ago, and the stability is slowly improving. Triggering a persistent slab avalanche is becoming less likely. Unfortunately, less likely doesn't mean impossible, and given the expected size of a triggered slide going for a ride will likely be unsurvivable. We often refer to this type of scenario as low likelihood/high consequence. In other words, we may be able to get away with a lot... until we don't.

The way we travel needs to reflect this uncertainty and unpredictability. The frustrating reality is that many slopes have the right ingredients to slide, and there's no way to know if your chosen path will hit the sweet spot that releases a deadly avalanche.

While not particularly satisfying, you can effectively keep out of harm's way by avoiding avalanche terrain, including the base of slopes greater than 30 degrees. Short of avoidance, you can reduce your risk by choosing to steer clear of shadier, more northerly aspects and by sticking to simpler, lower angled terrain.

Regioni coperte