Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

The threat of natural avalanche activity continues with increased winds.  We continue to receive reports of remotely triggered avalanches, naturals, and collapsing snow on a daily basis, thanks to our incredibly fragile snowpack.   Yesterday, a snowboarder was caught and injured in a persistent slab avalanche on Snodgrass.    You can easily avoid an encounter with today's avalanche threats by recreating on slopes less than 30 degrees that aren't connected to steep terrain above.  

Avalanche problems

  • Persistent Slabs

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

    On steep slopes that haven't already avalanched, you can easily trigger persistent slabs over buried facets and faceted crusts.  Evidence of the problem is clear:  there has been an ongoing parade of natural and human triggered avalanches reported from all but the sunniest aspects all week.  Be wary of traveling below steep, connected slopes: many of these avalanches were triggered remotely from low angle terrain and we continue to observe natural releases from wind loading.   While slabs are generally soft and 1 to 2 feet thick below treeline,  they will be thicker and denser in wind drifted terrain at higher elevations.  

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Gusty northwest winds are drifting recent snow into wind slabs on leeward and crossloaded slopes in wind exposed locations.  In wind loaded terrain features, you can trigger a slab large enough to drag you over rocks or push you into trees.   Shallow wind slabs could also step down and trigger a larger persistent slab avalanche.  Avoid steep terrain where you see obvious signs of fresh drifts, such as pillowy looking dunes, active windloading, or dense feeling snow.  

    12/16. Natural wind slab that ran on Red Lady.

Avalanche Discussion

Winds came in stronger than expected over the past 24 hours, and we're keeping the danger pegged at CONSIDERABLE for the ongoing threat of naturals and easily triggered persistent slabs.  Northwest winds increased overnight gusting into the 40's and 50's in the alpine.  In leeward or crossloaded terrain, the wind transported snow is adding stress to the ongoing persistent slab issues. This equates to more naturals, like the ones Evan spotted yesterday.  In some cases, winds are now adding cohesion to the slabs, which makes for wider propagation and surprising remote triggering potential.  Yesterday, I remotely triggered a small avalanche from almost a quarter-mile away from the slope.   The prolonged drought through early December created one of the more fragile weak layers I've ever seen.  Even in wind-sheltered slopes, where the snow is soft and doesn't feel very slabby, you can easily trigger an avalanche on slopes that haven't already flushed (See video).  The dangers are most pronounced at all elevations in areas that got more snow over the weekend (the Northwest Mountains and bordering terrain such as Mount Emmons, Coney's, and Snodgrass), and in terrain that is getting loaded by recent winds.    

Yesterday's accident on Snodgrass is a harsh reminder that small avalanches can have serious consequences in the wrong type of terrain.  The avalanche broke about a foot deep on a relatively small terrain feature, but the rider was carried into a tree, injuring his leg.  We'll have a full report on the incident soon.  

 

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