Bollettino valanghe

Banner Summit

Sawtooth Avalanche Center
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Pericolo valanghe

Sat
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

Avalanches are unlikely, and most slopes are safe. Sunshine this morning may initiate small loose snow avalanches. These slides are most likely on very steep, sun-drenched slopes that are sheltered from the wind.

Problemi valanghivi

  • Loose Wet

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

    Sun-induced wet loose avalanches are most likely on the first sunny day following a storm. Dozens of these slides occurred on Tuesday. Since then, avalanche activity has steadily dropped off as the slopes most prone to this problem have been picked clean by three consecutive days of direct sun. Wet loose avalanches, although less likely today, are still worth paying attention to and should be at the front of your mind when choosing a time and place to enjoy the mountains.

    This problem will start on slopes that face E-SE and work its way around to S and SW facing slopes as the sun tracks across the sky. Afternoon cloud cover looks like it'll put a cap on any potential wet avalanche issues on more westerly aspects this afternoon. Although likely to be small, wet loose avalanches can pack a punch, easily knocking you off your feet or pushing you into unwanted terrain. Use fresh-looking, recent, wet loose activity as an indication of where these slides are most likely again today. 

Avalanche Discussion

On more shaded aspects or in wind-affected alpine terrain, there are a few problems to keep in mind: 

  • Soft slabs: Recent wind may have built small, sensitive drifts in alpine terrain. A skier in the central Sawtooths was able to trigger one of these pockets on Wednesday. In the Banner Summit area and far northern Sawtooths, skiers triggered three small slab avalanches since Sunday. These avalanches shared the following characteristics: SE-E-NE aspects, slopes approaching 40 degrees in steepness, near or above about 9000' in elevation, and about 8-12" of new or windblown snow sitting above a subtle crust with a thin layer of small facets above it. These slides have not been big enough to bury people, but they can definitely push you around.  
  • Cornices: These huge chunks of snow become increasingly unstable as warm temperatures and direct sunlight cause them to sag and bend. Tuesday, several small cornice chunks peeled off during the day, triggering dry loose avalanches on the slopes beneath them. Large or small, be alert to the hazard cornices pose if you're traveling below them or on ridgelines. It is very difficult to accurately determine where a ridgeline's "terra firma" stops and the cornice starts; almost every avalanche professional has a story about a close call or accident they've had involving cornices. 
  • Dry loose - new snow: We observed several recent small, natural sluffs that failed on steep, shady NE-facing alpine slopes. Many appeared to be triggered by small cornice chunks falling onto the slopes. These sluffs probably won't be large enough to bury people, but they can quickly pick up speed and knock you off your feet or sled and carry you places you don't want to be. This type of slide is most likely in areas that received more than a few inches of new snow recently. 

Another storm is on tap for the weekend and it looks like we've got a good chance to hit "refresh" on the ski conditions. Expect a shot of snow on Saturday and again on Sunday with total accumulations in the 5-10" range by Monday morning. Some portions of the southern mountains such as the Pioneers may see 12" or more. With the new snow, expect to also hit "refresh" on our avalanche problems. The chances for small slab and loose snow avalanches will increase near the tail end and shortly following the storm. 

 

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