Bollettino valanghe

Gunnison

Crested Butte Avalanche Center
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Pericolo valanghe

Mon
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You are likely to trigger an avalanche on mid and upper-elevation slopes that face northwest to north to east.  This is evidenced by natural avalanche activity and human-triggered avalanches from Saturday. Remote triggering avalanches from below or connected slopes is a genuine concern as seen in this observation from Paradise Divide.  Shooting cracks and a collapsing snowpack are clear signs you have found unstable snow.  If you choose to travel on problematic aspects, select terrain with slope angles less than about 30 degrees without steep slopes above. 

Problemi valanghivi

  • Persistent Slabs

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

    You will find a fragile base to the snowpack on northerly and easterly aspects from the early seasonal snowfall back in October.  Over the past week, up to 2 feet of snow has fallen on top of these Persistent Weak Layers.  Observations from Saturday included natural avalanches, collapses, shooting cracks, remotely-triggered avalanches, and an unintentional skier-triggered avalanche.  The evidence seems pretty clear that triggered avalanches are likely on Sunday.  The danger will drop slowly in the coming days.  The problem is best managed through a conservative slope angle.   One potential exception to the distribution rose above might be found on high elevations southerly slopes.  Sunny slopes at upper elevations developed thin, continuous coverage in some areas just prior to this past week's snowfall.  Take a very cautious approach and investigate the snowpack on steep southerly slopes at upper elevations prior to descent.    

    This avalanche was remotely triggered from 600 feet away and grew large enough to bury or injure a person.  North-facing terrain at Paradise Divide. 11/25  

    Photo: Ben Pritchett

Avalanche Discussion

Early-season snowfall in October left a continuous blanket of snow across the mountains surrounding Crested Butte.  The first half of November was clear and dry which allowed most sunny slopes to melt out, unfortunately, this dry spell faceted and weakened the shallow snowpack on northerly and easterly aspects.  The resulting weak layers on the north half of the compass have now been buried by up to 2 feet of snow over the past week.  The recipe for a Persistent Slab avalanche problem.

Evidence from Saturday clearly points towards dangerous conditions on mid and upper-elevation slopes highlighted by the Persistent Slab distribution rose.  Visibility was poor for much of Saturday and I suspect the clear skies on Sunday will show more evidence of natural avalanche activity.  Conservative slope angle choices are the best way to avoid triggering an avalanche where you find cohesive snow resting above weak snow.

The snowpack remains very thin at low elevations and on sunny aspects which limits your terrain options.  Mother nature is funneling you towards aspects and elevations with the most significant avalanche hazard.  You could easily be injured by hitting buried objects, or worse, if you were dragged through the shallow snowpack by an avalanche.

Regioni coperte