Avalanche forecast

Southeast 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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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

 It's dangerous out there.  Numerous avalanches up to several feet thick were triggered or ran naturally yesterday, breaking in the new snow or near the ground.  Our fragile snowpack was delivered a solid punch on Monday night - one foot of snow and strong winds.    Blue sky, fresh powder, and a sketchy snowpack are the perfect recipe for an accident.   Dial back your ambitions and give yourself a wide margin for error for handling today's challenging snowpack.  Large avalanches can be remotely triggered from flat terrain adjacent to steeper terrain above.   Staying on consistent slope angles less than 30 degrees is your silver bullet for a safe day in the backcountry.  

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2

    Persistent slabs remain ripe for human triggering after Monday night's heavy snowfall.  On or near steep terrain, you can easily trigger slabs up to several feet thick that fail on weak snow near the ground.  Persistent slabs often surprise even the most experienced travelers: They give irregular feedback, they can propagate unusually wide distances, and they can be remotely triggered from below or adjacent to the slope.   Choose routes that stay off of, and out from underneath, steep terrain holding slab over weak layer structures, which are most common on the slopes highlighted by the distribution rose above.  Shooting cracks, collapses, and recent natural activity are all glaring red flags to stay on slope angles less than about 30 degrees.   

    12/29: A remotely triggered persistent slab below treeline. The crown was almost 3 feet thick.

  • Storm Slabs

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

    Monday night's storm spurred a storm slab cycle in the new snow.  Although new snow instabilities will be quicker to heal than persistent slabs, slabs of new and drifted snow remain a secondary concern today.  You are most likely to find this instability on steep terrain at higher elevations where slabs are thicker and stiffer from wind effects.  Shooting cracks, like this observation, are clear warning signs.    Look for feedback on small test slopes before considering more consequential terrain.  Storm slabs are entraining enough snow to be dangerous by themselves, but they can also step down and trigger larger persistent slabs on problematic aspects.    

    12/29: A large storm slab that released from a wind drifted ridgeline on Schuylkill Ridge.

Avalanche Discussion

Yesterday we got a small glimpse into the natural avalanche cycle spurred by the storm that brought 8" to 20" of snow (up to 1.3" SWE favoring the Northwest Mountains) and strong southwest winds.  Whetstone produced a cycle of large persistent slabs breaking near the ground, some triggered by smaller storm slabs.  Along the Slate, we observed a cycle of small to large storm slab avalanches involving the new snow, and a few more persistent slabs.  Today, we'll get our first clear views into the rest of our forecast area.  Let us know what you see by submitting an observation or emailing us a few photos ([email protected]).  

Travelers across our whole forecast area reported tender conditions yesterday: remotely triggered persistent slabs breaking a few feet thick, cracking and collapsing on both the storm interface and on weak layers near the ground.  This won't change today, particularly for the persistent slab problem.  Sugary weak layers on the ground have been consistently producing avalanches and obvious signs of instability all month, even during dry spells.  Fresh off the largest storm of the month, persistent slabs will be easy to trigger today on slopes that haven't already avalanched.  With tender slabs breaking several feet thick, even small terrain features can get you into trouble.  Be wary of crossing onto or just below small rollovers, clearings in the trees, cut banks above creeks, etc.  Terrain that is normally benign during mid-winter conditions might surprise you today.  

Join us tonight at 7 p.m. for our first Virtual Fireside Chat Speaker Series.  We've got Wendy Wagner, the director of the Chugach Avalanche Center, talking snow, avalanches, mentorship, and the skier turned sledneck phenomon.  It's on zoom so you can wear your sweatpants, or no pants, if you prefer: Launch Zoom - Zoom

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