Bollettino valanghe

Northwest Mountains

Crested Butte 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

Dry Loose avalanches, or sluffs, require your attention in steep, sheltered terrain that faces the north half of the compass.  If you notice the snowpack is very weak and soft on steep slopes then you should expect some moving snow as you descend.  Most sluffs remain small in size, but big enough to take you for a ride if caught.  The consequences of a small avalanche could be serious if you are pushed into a terrain trap.  Use sluff management techniques to reduce the chance of being caught in your sluff or stick to slopes less than about 35 degrees where sluffs are unlikely to initiate.

 

Problemi valanghivi

  • Loose Dry

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    In wind-sheltered terrain on the north half of the compass, you can trigger loose snow avalanches on steep slopes where the upper snowpack is weak and cohesionless.  Most sluffs are harmless, but a few could gouge through the weak snowpack and entrain more snow than expected.  Use caution above terrain traps such as long-running gullies or above trees and cliffs.  You can manage the problem by riding off the fall line or pulling out of the way to let your sluffs go past you.  You can avoid the problem by riding on lower slope angles less than about 35 degrees.  

    1/3:  A skier triggered sluff on Schuylkill Ridge that gouged through the snowpack.  

Avalanche Discussion

Due to persistent cold and dry weather, the snowpack slowly weakens through the faceting process.  You will find a generally weak snowpack in sheltered terrain on the north half of the compass.  Evidence of the Dry Loose avalanche problem increased in recent days.  Observations from Schuylkill Ridge and Happy Chutes (Mount Emmons) reported sluffs gouging through the entire snowpack, although these slides were not big enough to bury you, they certainly could take you for a nasty ride into trees or rocks.  Gouging sluffs are more likely to be found on slopes with a shallower snowpack, often due to previous avalanche activity this winter.  Additionally, loose avalanches on longer slopes could grow bigger than expected as they descend and accumulate mass.  Today's weather forecast calls for a few inches of new snow which could add more volume to the problem as the day progresses.

Slab avalanche concerns have greatly diminished over the past two weeks hence the removal of Persistent Slab from the problem list.  Human-triggered slabs are unlikely, but not impossible, where you find hard slabs of wind-drifted snow from previous northerly wind events.  The problem is largely dormant but poor structure exists in isolated places across the landscape.  On Thursday, explosive control work released a hard slab avalanche on a drifted west-facing feature with an airblast.  Consider this unlikely possibility on heavily drifted features, unsupported slopes, and extreme terrain.

Unsettled weather is on tap for the next week, and with very weak snowpack structures in many places, it will not take much new snow to create a rise in avalanche danger.  Keep reading the forecast and be prepared for increasing avalanche danger once Mother Nature delivers.

 

Regioni coperte