Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Dangerous avalanche conditions exist.  You are likely to trigger an avalanche particularly on slopes that face the north half of the compass.  You can reduce your risk of avalanche by choosing slopes less than 30 degrees in steepness that are not connected to or beneath steeper terrain.  Low-elevation southerly features offer less dangerous options as the recent large storm fell mostly on bare ground and has received less wind-loading.

Avalanche problems

  • Persistent Slabs

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

    2 to 4-foot slabs have formed over a very weak foundation. That weak foundation exists on slopes that face the north half of the compass. These avalanches could still run naturally where wind-loading occurs and will be sensitive to human triggers. You can also trigger this avalanche problem from low-angled slopes connected to steeper terrain.  Slabs continue to settle and stiffen which means you can remotely trigger an avalanche from a distance and avalanches may propagate much wider than you expect.

    This was a remotely triggered avalanche on 12/9, that propagated widely through the terrain and would easily have buried a person. 

  • Storm Slabs

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

    The recent storm has created slabs, that can release within the storm snow, even on slopes that were bare ground a week ago. These 2 to 4-foot slabs will further grow in size and sensitivity near wind-loaded terrain features. The wind direction shifted to the northwest which resulted in wind-loading on the southern half of the compass.  Expect drifted southerly terrain to be more dangerous than sheltered, southerly slopes. 

Avalanche Discussion

Looking at the big picture, the mountains around Crested Butte have received between 2 and 4+ feet of new snow over two days with a whopping 4.5 inches of snow water equivalent measured on Kebler Pass.  The snowfall stopped overnight but west to northwest winds will continue to drift terrain features.  The most dangerous terrain will be on the north half of the compass where the impressive storm snow rests on a very weak base of faceted snow.  Expect that you can easily trigger an avalanche on northerly-facing terrain.  Consider what terrain is above you and what is adjacent as remotely-triggered avalanches are on the menu.  Plan your routes accordingly so you do not find yourself directly below suspect slopes.  Keep in mind that wind-loading will maintain the possibility of natural avalanches at upper elevations.  

Southerly terrain is not as worrisome as shaded slopes, but with virtually no visibility over the past two days, we have yet to make sense of recent avalanche activity.  You can be confident that upper elevation southerly slopes are seeing wind-loading from west to northwest winds.  Use caution around all drifted terrain features on the south half of the compass today to hedge your bets against the uncertainty.  2 to 4 feet of snow coupled with wind-loading will make for avalanches large enough to bury, injure, or kill you on sunny terrain.

Managing overhead terrain and slopes angles will be your single best defense against triggering an avalanche this weekend.

Regions covered