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 6 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Triggering a large avalanche is unlikely. Small, isolated wind drifts exist near ridgelines in upper elevation terrain—some of these may remain sensitive to your weight. If prolonged periods of sunshine occur today, natural and human-triggered loose snow avalanches (sluffs) will become possible on very steep slopes.

Problèmes avalancheux

  • Wind Slabs

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

    The 12-16 inches of new snow that fell earlier in the week was blown into drifts and slabs in upper elevation terrain. Observations since then indicate that these wind slabs have become less reactive and slopes where you could trigger one are fairly isolated. However, a group in the neighboring Sawtooths & Western Smoky zone triggered a small wind slab yesterday (video above/right)—so I wouldn't write off the possibility in this zone.

    Continue to look for drifted and pillowed areas in starting zones directly below prominent ridgelines. Surface texture and denser/stiffer snow are tell-tale signs of a loaded slope. While it's unlikely these wind slabs would be large enough to bury you, they could still be dangerous in consequential terrain.

    ADDITIONAL DISCUSSIONThe forecast today is calling for continued cool temperatures and cloudy skies, decreasing the risk of wet snow avalanches. However, this unsettled spring weather can be tough to predict. If the sun pokes out today for a prolonged period of time, both natural and human-triggered wet snow avalanches will become possible on steep slopes that are getting direct sunshine. Keep a close eye on the cloud cover, and evaluate overhead terrain if conditions warm up more than expected.

Avalanche Discussion

When spring weather serves up warm, sunny days and clear, cold nights, we enter a predictable "diurnal" pattern of avalanche danger. Conditions are safe at the start of the day when the snowpack is frozen, and the possibility of triggering a wet slide increases as the day warms up. But the unsettled and snowy spring weather we've been experiencing—while nice for catching up on powder skiing/riding we missed in February—has lead to a less clear-cut pattern of avalanche conditions. Many of us expect a more stable snowpack in the spring, and while you're less likely to trigger a large avalanche now compared to mid-winter, there are more ways that you could trigger something. That something may come in the form of:

  • Triggering a larger persistent slab avalanche remains possible in the SE corner of the forecast area, where recent snowfall fell on a thin snowpack weakened by the February drought.
  • Wind slabs become an issue with each spring storm, and may form unexpectedly with localized spring squalls.
  • The likelihood of wet snow avalanches and sluffs is directly tied to the cloud cover, which is notoriously unpredictable during this unsettled spring weather. Even when the forecast calls for cloudy skies, be ready to adjust your plans if the sun comes out. New snow can slide nearly instantaneously the first time it gets hit with spring sunshine.
  • This last storm laid down a blanket of unusually light, dry snow in our northern mountains. Loose snow sluffs, while generally a "manageable" problem, can catch you by surprise in steeper terrain.

Take-home point? You might have to check your expectations of what spring should be like at the door. Conditions are not as predictable and easily-managed as they might normally be. Keep an eye out for the problems described above, and enjoy some late-season powder!

Régions couvertes