Bulletin d’avalanche

Gunnison

Crested Butte Avalanche Center
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Danger d’avalanche

Mon
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

A Special Avalanche Bulletin remains in effect.  Widespread collapses, numerous large triggered avalanches, and a fatality on Friday just north of our forecast area all highlight dangerous conditions.   We are in the wake of a storm that produced extensive natural avalanche activity and formed slabs 2 to 3 feet thick over a fragile weak layer.   On slopes that haven't already flushed, you can easily trigger a dangerous slab from on or below a steep slope.   Conservative terrain choices are essential today.  

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2.5

    You can easily trigger slabs 2 to 3 feet thick that fail on fragile facets and faceted crusts below the recent storm snow.  Avalanches can be remotely triggered from below steep slopes and they can propagate surprisingly wide distances.  There is a mountain of evidence showing that the problem is easy to trigger and most suspect on west to north to southeast aspects.   To avoid the problem, choose slopes that are consistently less than about 30 to 35 degrees that don't connect to steeper terrain above you.

    2/26:  Looking up at the crown of a large persistent slab avalanche that surprised a group of skiers on Saturday near Kebler Pass.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Warming temperatures and sunshine could trigger small wet loose avalanches on steep, sunbaked slopes today.  The problem will be obvious if it develops: you'll see rollerballs, pinwheels, or small sluffs starting to shed from very steep terrain and from below rock outcrops.  Stay wary below steep gullies or in consequential terrain if you feel the snow surface getting sticky or gloppy.  There is isolated potential for a small wet loose avalanche to trigger a larger persistent slab where the problems overlap.

    This photo from the archives shows what a wet loose avalanche looks like.  

Avalanche Discussion

Since the storm cleared out on Friday morning there have been several serious avalanche accidents regionally.  On Friday afternoon, three snowshoers and two dogs were caught in an avalanche near the town of Marble. Two people were partially buried, but able to dig themselves out of the snow. The other person and both dogs were buried and killed.   Our deepest condolences go out to the friends and family of the deceased, and everyone affected by this tragic accident.  Yesterday, a skier was caught and seriously injured in a large avalanche in the San Juan Mountains. The skier was evacuated by Flight for Life.  Locally, a group of skiers had a close encounter with a large triggered avalanche, and there were several more remote triggered slides large enough to bury someone (Example A, Example B).  Observations of widespread collapsing and shooting cracks unanimously highlight that it's still unstable out there.   That will be slow to change given the nature of our troublesome weak layer, especially below treeline where the layer is most fragile.  We are starting to see signs of improvement at higher elevations, where the problem is starting to shift towards a lower likelihood but higher consequence setup than its neighboring elevation bands.  Regardless, it's another day for conservative travel habits if you are traveling on slopes facing west to north to southeast.  

With temperatures rising close to freezing today, watch for small wet loose avalanches to run naturally on steep, sun-baked slopes where the snow surface gets moist or wet.  There is also some concern for moving sluffs or surface warming to trigger a larger natural persistent slab where the problems overlap. 

Régions couvertes