Avalanche forecast

Gunnison

Crested Butte Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Dangerous avalanche conditions prevail for Thanksgiving Day following a significant winter storm that produced over 100 natural avalanches and 23 human-triggered avalanches. Lingering storm slabs and widely propagating persistent slabs are the very real avalanche problems that require management today. You can avoid these avalanche problems by riding lower elevations southerly facing slopes that had dry ground or very little snow before this week, or by traveling on slope angles less than 30 degrees that are not connected to steeper slopes above. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    A significant avalanche cycle has occurred over the last couple of days, following a major winter storm. These avalanches are breaking 2 to 4 feet deep and releasing on weak faceted snow that formed earlier this winter. The upper snowpack is gaining strength, and this will decrease the obvious signs of instability in some areas. However, the weak snow in the middle or at the bottom of the snowpack will remain problematic for some time to come. The most problematic aspects face west, north, east, and some southeast-facing slopes. The current travel advice is to avoid this avalanche problem. To avoid this problem, travel on low-angled slopes less than about 30 degrees that are not connected to steeper slopes above. 

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Instability within the 2 to 3 feet of storm snow is still settling out.  We can't yet rule out continued avalanche activity on all aspects generally above 11,000ft. You can reduce your chance of triggering a storm slab, by avoiding previously wind-loaded terrain, and by keeping your slope angles under 35 degrees. 

    A smaller storm slab avalanche is visible on the south-facing slope in the foreground, while a larger persistent slab avalanche is in the background. 

    Photo: Evan Ross

Avalanche Discussion

Cloud cover decreased on Wednesday, allowing us to start documenting the significant avalanche activity during this week's major winter storm. This link will pull up a graph of the avalanche activity documented so far this week. Currently, we have 123 avalanches in this data set. The most widespread avalanche activity occurred on west, north, and east aspects. This should be no surprise, as these aspects held well-documented weak and faceted snow that is now buried under this week's storm snow. There were also several widely propagating avalanches on SE-facing slopes, primarily above 11, 600ft, and we have added this aspect to the persistent slab avalanche rose. 

Storm slab avalanches, or avalanches breaking within the recent 2 to 4 feet of new snow, have also occurred around the compass. This avalanche problem will heal much faster than the persistent slab avalanche problem. They will eventually come off the problem list or transition into a wind slab avalanche problem as we look ahead to an increase in wind speeds on Friday afternoon into the weekend. 

The major winter storm and atmospheric river event produced 2 to 4 feet of snow (2.3" to 3.7" SWE) from Monday night through Wednesday morning. The wind direction during this storm varied from southwest to west to northwest through the storm. 

The snowpack is going through its early-season growing pains, and the danger is elevated, but here are some reasonable ways to reduce your risk:

  • Choose low slope angles of less than 30 degrees without overhead hazards. Persistent slab avalanches can be remotely triggered from lower-angled terrain connected to steeper terrain, so this situation needs to be avoided. 
  • Travel on those below treeline, southerly slopes that were dirt and grass a week ago while monitoring for the threat of any mid-storm instabilities. 
  • Put on your favorite Christmas movie (Zach's picks: Elf, Love Actually,  or Bad Santa if you're feeling a little risky) and start basting that turkey. The danger will gradually subside, although we'll need to use a conservative mindset through the holiday weekend with our persistent slab issue.  

Regions covered