Avalanche forecast

Gunnison

Crested Butte Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The lingering potential to trigger a large and dangerous avalanche on colder, shadier aspects should dictate your travel habits.  A large remotely triggered avalanche near Irwin on Friday, numerous shooting cracks in Cement Creek on Sunday, and continued unstable pit results near Mt. Emmons yesterday highlight that our buried weak layers remain a threat on some slopes.  If you are riding in steep terrain on the northern half of the compass, carefully assess the snowpack for strong over weak structure. Choose terrain that both minimizes the chances of triggering and minimizes the consequences of getting caught in a large avalanche.  Watch for fresh drifts forming today from increased northerly winds.  

Avalanche problems

  • Persistent Slabs

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

    On the northern half of the compass, you can trigger a dangerous slab avalanche that breaks up to several feet thick on weak faceted snow that was buried last month. Slabs can be triggered remotely from below or adjacent slopes. Collapsing and cracking are clear signs of instability, although direct feedback on this problem has become less frequent. The more likely areas to trigger today's persistent slabs appear to be where the total snowpack height is between 1 and 2.5 meters deep or in shallow trigger points such as rock bands or margins of slabs. When in doubt, head for southerly aspects, lower consequence terrain, or slope angles in the lower 30-degree range and less. 

    This large persistent slab avalanche was remotely triggered on 3/18. 

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Winds increased overnight out of the north and are strong enough to scrape dry snow off of northerly fetches and deposit it below leeward ridges or cross load it into gullies and behind rollovers.  Without much snow available for transport, slabs should remain small in size. However, they'll also be stiff enough to break around you and knock you off your feet.  Look for dense and firm deposits of freshly drifted snow or blowing snow onto steep slopes to identify the problem.  Northerly winds have a way of working down valleys and forming drifts behind rollovers at lower elevations too.  

Avalanche Discussion

Northerly winds increased last night, blowing moderate speeds near treeline and stronger above treeline.  There's no fresh snow to blow around, but those pesky north winds have a way of working into old powder stashes on north-facing terrain to find snow available for transport.   Fresh wind slabs should be fairly small and easy to recognize if you pay attention to surface textures.   

The most pressing concern remains...yes, you guessed it...persistent slabs.  The snowpack remains winter-like on the northern half of the compass.  The threat of triggering a persistent slab continues to slowly diminish with each passing day of dry weather. However, the consequences are still serious. Slabs are dense and up to several feet thick.  Each slope is caught up in its own tug-of-war between the strength of our dry spell weak layer and the stress of the overlying slab.  Many slopes lost that battle back in late February and ran naturally.  Some slopes have gained enough traction on the weak layer in the past week or so that they are now conditionally stable.  And others hang in the balance waiting for someone to hit a trigger spot.  Here are a few strategies to reduce but not eliminate your risk if you are looking to ride on steeper northerly aspects.  1) Go towards slopes that show clear evidence of avalanching during the past month.  Partially refilled bed surfaces have not been as active, and potential sizes are smaller.   2) Go towards slopes with a consistently deep and uniform snow coverage (deeper than about 2.5 meters) and shy away from rock bands or terrain where winds have created variable snow depths.   This sequence of photos of a recently triggered persistent slab outside of our forecast area shows how shallow trigger points can be hidden from view until it's too late.  If all of this sounds a bit too complicated, you can reliably avoid the problem by sticking to lower angle terrain or moving to southerly aspects which have a more spring-like snowpack.  

Regions covered