Bulletin d’avalanche

Southeast Mountains

Crested Butte Avalanche Center
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Danger d’avalanche

Fri
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

24-hour snow totals are averaging between 2 and 4 inches. The persistent slab avalanche problem is slowly becoming less likely to trigger day by day, but by no means is it going away. Continue to practice good travel habits such as riding one at a time through avalanche terrain, and managing the persistent slab problem through your terrain choices.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Slabs 1 to 3 feet thick exist over weak facets near the bottom of the snowpack. The problem has been most active on northerly and easterly facing slopes, with some avalanches on westerly facing terrain as well. Persistent slabs are gradually becoming more difficult to trigger and signs of instability are becoming less frequent.  However, if you cross the wrong slope or the wrong spot on a slope, a single collapse can result in a surprisingly large avalanche involving most of the snowpack.  Persistent slabs could break wider than you expect, and they can be triggered from flat slopes connected to steeper terrain above you. You can reduce your risk by traveling on slopes where the problem isn't highlighted above, or by traveling on small terrain features without terrain traps.  You can avoid the problem on slopes consistently less than 30 degrees. This avalanche problem becomes more isolated in its distribution and is the least likely to be encountered at elevations below 10,500ft.    

    12/8: The flank of a persistent slab avalanche that was remotely triggered from lower on the slope.

Avalanche Discussion

It is hard to say where the most snow fell over the last 24 hours. Given the SE wind direction, we would expect the SE Mountains to be the winner, like areas in upper Brush Creek and upper Cement Creek. A weather station out by Taylor Pass is showing 4" of snow, and that is similar to Schofield Pass. While Irwin's weather station is showing around 2" and CBMR is about 3". The weather stations that have a higher elevation are showing more snow, and that is in part due to the relatively warm temperatures during the last 24 hours. Wind speeds have remained light during this time. So this new snow will simply add a little cream on top of some already good riding conditions that can be found out there. 

When the highlight of the avalanche forecast is 2 to 4 inches of snow, then you can tell things have gotten quiet. The last documented avalanche activity occurred last Sunday 12/10. Before this, there has been a downturn in avalanche activity since the last natural avalanche cycle occurred around 12/4. The snowpack structure remains poor in areas highlighted by the persistent slab avalanche problem. While time since the last loading event and the mild weather are leading to the avalanche problem having become less reactive. When this type of avalanche problem quiets down, it becomes difficult to summarize a blanket statement for travel advice. There are some groups stepping out in their terrain choices and others enjoying the low-angle terrain that is riding really well. We must always remember that persistent slabs are notorious for their deceptive behavior. As Zach wrote the other day, "Your assessments should include more than just 'Can I trigger it?' You need to also ask yourself, 'Do I have uncertainty?' and 'What are the consequences if my assessments are wrong?".

 

The Fireside Chat series kicks back off this Saturday 12/16. Here is more info. We hope to see you there!

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