Avalanche forecast

Southeast Mountains

Crested Butte Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Up to 10 inches of new snow accumulated in the past day.  You can trigger an avalanche in the storm snow and on weak layers near the bottom of the snowpack.  Avalanches that break near the bottom of the snowpack would be deadly and dictate your terrain choices.  Remain wary of wind-affected terrain as these are the most likely places for you to release a deep failing avalanche.  Conservative terrain, slopes around 30 degrees or less that are free from overhead hazards, remain your best defense against triggering a deadly avalanche.

 

 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–3

    Slabs ranging from 3 to 6 feet thick have formed around much of the compass and at all elevations over faceted weak layers in the lower snowpack. These weak layers have adjusted to their current load and were slowly becoming more difficult to trigger. However, the variability in the slab depth, especially at near and above treeline elevations, is creating more locations for lighter loads, such as the weight of a human, to affect those weak layers and release the avalanche problem. These persistent slab avalanches can propagate widely through the terrain, or be remotely triggered from low-angle slopes connected to steeper slopes. You can reduce your risk by traveling on slopes with a deep, uniform snowpack. While you can further avoid the problem by traveling on slope angles that are consistently less than 30 degrees and not connected to steeper terrain above. 

     

    1/4:  A destructive natural avalanche in Red Lady Bowl broke full-width last week.  This avalanche would be hard to survive.

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5

    Fresh snow available for transport has combined with southwest-to-west winds and is forming a new round of wind slabs.  Wind slabs most commonly form below the lee sides of ridgelines and in cross-loaded terrain features at near and above treeline elevations.  A chance exists for avalanches in the storm snow to cause an avalanche to break deeper into the snowpack.

    Example of an old wind slab that failed on a cross-loaded terrain feature. 

Avalanche Discussion

Snow totals exceed a foot of settled storm snow in the Northwest Mountains and up to 10 inches in the Southeast Mountains.  In the Northwest Mountains, the avalanche danger is largely driven by the new snow accumulations.  Reports from yesterday afternoon, near Irwin, indicated sensitive Storm Slab avalanche conditions in 10 inches of storm snow.  Snowfall continued to accumulate last night and now Storm Slabs are over a foot thick in sheltered areas and a bit deeper where the wind has drifted snow onto leeward slopes.  Additionally, observations of Surface Hoar formation from this past weekend raise suspicions about new snow bonding to the old surfaces (ob 1, ob2).  Carefully investigate the storm snow before you consider entering terrain near or steeper than 35 degrees.  Drifting snow or cracking in storm snow are clear indications of unstable conditions in surface snow.

In the Southeast Mountains, the danger is driven by the chance of triggering an avalanche deeper in the snowpack well beneath the recent storm snow.  In locations where you find or anticipate finding, less than about 5 feet of depth there is an increased chance of triggering a deeper avalanche.  The new load may make triggering a deeper avalanche more likely due to the increased burden.  If you are uncertain about depths or the chance of triggering an avalanche on a deep weak layer, then defer to conservative low-angle terrain to greatly reduce your risk.  Avalanches in the storm snow are still possible in the Southeast Mountains where you find storm totals nearing a foot and on drifted terrain features.

Snowfall continues for the next three days.  As snowfall stacks up the avalanche hazard will slowly increase with the new loads.  Stay tuned in the coming days to follow the changing conditions.

Regions covered