Bollettino valanghe

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Pericolo valanghe

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2 · Moderato
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Non aggiornato — questo bollettino è scaduto 7 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Avalanche conditions are most dangerous on wind loaded slopes. The wind has transported the new snow into touchy drifts and slabs—you're likely to find these in upper elevation, wind-exposed terrain. The snowfall is also adding weight to buried weak layers, and it's possible to trigger an avalanche 1-3 feet deep—even on wind-sheltered slopes. Expect the avalanche danger to rise overnight as the next significant round of snowfall hits our area.

Problemi valanghivi

  • Persistent Slabs

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    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2

    Persistent weak layers buried 1.5-3 feet deep have been slowly loaded by recent snowfall. A fairly constant trickle of precip since New Years, as well as yesterday's 8-12 inches of new fluff, have kept these layers on edge but so far hasn't been enough to cause widespread instability. That doesn't mean you should feel good about the snowpack you're sliding or riding on—it's still possible to trigger a dangerous avalanche. If we go back to the basics, we have persistent weak layers, and they are getting loaded with new and windblown snow. It's likely these layers will hit a breaking point in the coming days as new snow continues to add up, and it makes sense to start dialing back the slope angles before that happens.

  • Wind Slabs

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

    Observers yesterday only found wind slabs in the most wind-exposed, upper elevation terrain. But where wind drifts were found, they were reactive to a rider's weight. Some weather stations reported an uptick in wind overnight, so additional wind transport may have taken place since yesterday. I'd expect these wind slabs to be less touchy today, but you'll want to avoid any slope with wind-drifted snow. 

Avalanche Discussion

Snowpack conditions within our forecast area have begun to diverge. Following the New Year storm, a nearly constant trickle of snow has fallen in our northern and western mountain ranges. Additionally, yesterday's storm, tonight's, and the snowfall this week continue to favor these same areas—the Western Smokys, Sawtooths, Banner Summit, and to some extent, the Soldiers. For the first part of the winter, we had fairly uniform conditions across the forecast area. That situation has changed, and will continue to change, over the coming week.

In our northern and western mountains, the persistent weak layers we've been talking about all winter are becoming quite deeply buried. The surface hoar and depth hoar from early in the winter are now buried beneath 3-4 feet of snow. A newer weak layer that formed prior to the New Year's storm is 2-3 feet deep. With another 12-16 inches of new snow in the forecast tonight, these weak layers continue to get pushed further underfoot and are becoming harder to trigger. But it should come as no surprise that triggering an avalanche 2-4 feet thick is no joking matter. It's also becoming more difficult to predict what these deep weak layers will do under the slow but constant loading we're currently experiencing.

The Galena Summit area, our Eastern Mountains, and especially the Wood River Valley have received overall snowfall since the start of the New Year. These areas have a snowpack that's a bit thinner with more prominent persistent weak layers but have received less recent loading to aggravate them. These weak layers are 1-3 feet deep and are more easily impacted by the weight of a rider. Will these areas receive enough snow over the coming days to make these layers wake up? Time will tell.

But our area does have one thing in common. Even if it comes in different forms, there's a high degree of uncertainty in how our snowpack will react to the extended storm cycle we're experiencing. Uncertainty means building more margin for error into our terrain choices. The best approach—and the one I plan to take—is to sit back, enjoy some fantastic low-angle powder riding, and see what shakes out.

Regioni coperte