Bollettino valanghe

Soldier & Wood River Valley Mtns

Sawtooth Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
Open full map
Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

It's becoming less likely, but triggering a large avalanche remains possible in the eastern portion of this zone (the Little Wood drainage, southern Wood River Valley, Pioneer Mtns, and near Bald Mtn). In these areas, weak snow beneath a 1-2 foot thick slab remains a concern—primarily on upper elevation, shady slopes. Avalanches are more likely where fresh or recent wind drifts exist, but sheltered slopes are not guaranteed to be safe. Avalanches can be triggered remotely—from flatter terrain below, above, or to the side of steeper slopes. Periods of direct sunshine could cause wet loose snow avalanches on very steep slopes. 

Problemi valanghivi

  • Persistent Slabs

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

    Persistent slab problems are more commonly a mid-winter problem, but an exceptionally dry February left us with a thin, weak snowpack in much of this zone. Last week's 16-20 inches of snowfall produced a large amount of natural persistent slab avalanche activity (photo at right/above). While this problem is slowly improving, I continue to remain wary of upper elevation, shady (E-N-W facing) aspects where this snowpack layering is most common. Even though it's nearly April, you could still trigger a slide that breaks hundreds of feet wide.

    Persistent slab avalanches can fail in ways that catch even experienced backcountry users by surprise. You may be able to trigger slides remotely: from flatter terrain above, below, or to the side of a steep slope. Choosing lower angled terrain not threatened by steeper terrain above is the only way to safely "manage" this problem. While these avalanches are most likely on recently wind-loaded slopes, they can occur on slopes with no recent wind-drifting as well. 

    ADDITIONAL DISCUSSIONThe forecast today is calling for continued cool temperatures and mostly 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!

Regioni coperte