Bulletin d’avalanche

Banner Summit

Sawtooth Avalanche Center
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Danger d’avalanche

Sun
Alpin
1 · Faible
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 7 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Avalanches are unlikely and most slopes are safe. Isolated areas of unstable snow may exist in pockets of wind-drifted or pillowed snow. It'd be a stroke of bad luck but triggering an avalanche on weak layers buried 2-6 feet deep remains a remote possibility on very steep, rocky, wind-affected slopes at upper elevations. The avalanche danger is expected to increase tomorrow due to snowfall and wind.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    1–2

    Due to it's lower elevations, last week's wind events likely had less impact on the Banner Summit zone, but you may be able to find isolated wind slabs that could be reactive to the weight of a skier or rider. Look for these wind drifts at upper elevations on the downwind side of prominent terrain features like ridges, mid-slope gullies, and cliff bands. Pay attention to the feel of the snow beneath your skis or sled, and use extra caution if you find steep slopes with hard or stiff snow.

    ADDITIONAL DISCUSSIONOn Tuesday, Ethan checked out an avalanche that failed on an east-facing slope near 8800' on Copper Mountain (photo, observation). Limited direct observations of this layer suggest that it's not likely an issue in the near term. That said, it's worth taking the time to dig a quick pit to see how recent snow is bonding to the older snow below.

    Triggering a 4-6 foot thick persistent slab avalanche has become very unlikely. It would take a dose of very bad luck, but it may be possible to trigger one of these monsters in very steep (over 35 degrees), wind-swept, alpine terrain.  

Avalanche Discussion

It's been a week since the end of the last storm—in our southern mountains, it's been even longer. During this mid-winter dry spell, we've experienced the full gamut of weather: wind, cold temps, warm temps, sun, clouds, more wind—you name it. This has left us with a snow surface that's equally variable. In wind-sheltered terrain, you're likely to find that the snow surface has turned to "recycled powder", also known as near-surface facets. On sunny slopes, a crust exists that may have facets above and/or below it. On Wednesday, Ethan found an ugly and relatively widespread crust and facet combination at middle elevations in the Soldiers (video). Once you get into wind-exposed terrain, all bets are off and you're likely to find anything and everything—wind-hardened surfaces, stiff drifts, sun crusts, and near-surface facets. A good rule of thumb is this: the slopes where you've been finding the best riding conditions are usually the weakest snow surfaces.

While the storm arriving this afternoon is looking less impressive than it once was, we still stand to bury these surfaces throughout much of the forecast area. In our northern and western mountains, we may see enough snowfall—combined with wind—to create a slab atop these new weak layers. Tomorrow, our job will be to see how the old snow surface responds to the new load. As Scotty said on Wednesday, "Today's canvas is tomorrow's problem". But for the canvas to become a problem, we need a painter—snow and wind. Will this painter be a Michaelangelo or a rank amateur? We'll know more by tomorrow morning, but I say bring it on! 

Régions couvertes