Avalanche forecast

Gunnison

Crested Butte Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A Special Avalanche Bulletin is in place for the mountains surrounding Crested Butte.  Significant snowfall on Friday and Saturday stressed a weak snowpack and triggered avalanches are likely.  Terrain from Kebler Pass through Paradise Divide through Schofield Pass is the most hazardous as these locations received the most snowfall with slabs up to 18" in sheltered areas and deeper on drifted features.  Expect that you can easily trigger avalanches that are large enough to bury you in snow favored areas.  The terrain in the Southeast Mountains that border the Northwest Mountains are included in this Special Avalanche Bulletin.    

Avalanche problems

  • Persistent Slabs

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

    Friday and Saturday snowfall built slabs on top of very weak snow surfaces.  Observations from Saturday indicated a touchy snowpack with numerous small avalanches triggered below treeline (poor visibility prevented information gathering in alpine areas).  Some avalanches were triggered remotely.  The largest avalanches are expected to be found in the Northwest mountains on drifted terrain features at mid and upper elevations.  Even shallower soft slabs in sheltered terrain can gather more volume than expected due to the entrainment of weak snow below the slab.  The smallest slabs are likely to be found in areas east of Crested Butte.

    Mid-track in Thanksgiving Bowl on Schuylkill Ridge on 12/11. This large avalanche ran through everything in that direction and most of the slope behind the photo.

Avalanche Discussion

As you have read in the Bottom Line, there is a Special Avalanche Bulletin in place.  Settled storm totals range from 6 to 18-inches (potentially more in the Ruby Range but little data is available).  A true pile of observations flooded the CBAC yesterday (thank you, I'm calling it ob-apalooza!) that clearly illustrated a touchy snowpack on most aspects below treeline. Take a look at the observations page to see around 20 small, human-triggered avalanches.  All of the observations come from below treeline sites because of the poor visibility and dangerous conditions.  I expect that larger avalanches occurred on larger terrain features in the Northwest Mountains; they just were not observed yet (CBAC staff will document this activity today).    

The greatest hazard will be in the Northwest Mountains.  It will remain likely for you to trigger an avalanche on drifted and sheltered terrain on most aspects that are 35 degrees or steeper.  The largest avalanches will run on drifted terrain features at mid and upper elevations or areas deeper into the Northwest Mountains.  Winds may continue to load some slopes near and above treeline today keeping the pressure on weak layers.  Expect upper elevation terrain to produce large avalanches that will be big enough to bury you.  In sheltered areas, slabs will be smaller, but the weak, old snow below is likely to be entrained as avalanches run and will create debris piles large than you would expect.  Conservative decision-making and thoughtful travel techniques will be required to manage the avalanche hazard effectively.  Expect dangerous avalanche conditions and choose terrain that will help to minimize your risk.  The simplest solution is to choose lower angled slopes without avalanche hazards above.  Observations from yesterday seem to hint at southerly-facing slopes as potentially problematic as well where the new snow fell on slick, "facety" crusts.  Northerly winds will likely have drifted alpine southerly-facing slopes overnight.  

The Southeast Mountains have settled storm totals ranging from 6 to 13-inches.  Here the avalanche problem will be smaller in size, but still capable of entraining more mass than expected due to the weak snowpack below.  The border area of the Southeast Mountains where it meets the Northwest Mountains will be the most concerning.  This includes terrain on Mount Emmons, Anthracite Mesa, and Snodgrass Mountain.  Drifted areas near and above treeline across the Southeast Mountains have the potential to produce large avalanches capable of burying you, just not nearly as common as in the Northwest Mountains.  Overall the Southeast Mountains are less concerning because the avalanche size is smaller, but taking a ride into a stand of trees or rocks can still cause serious harm.

We are not "out of the woods" just yet even though the sun will shine today and the mountains will be inviting.  The previous snowpack was very weak and now a slab is resting above in many areas.  Sensitivity will decrease today, yet avalanches remain likely for human-triggering and we can't rule out a natural avalanche on upper elevation terrain that receives wind-loading today.  Continue to treat avalanche terrain with respect, and anticipate that it will take longer than usual for the danger to drop.   

Regions covered