Colorado Backcountry Skier Triggers Massive Avalanche Near Crested Butte

Colorado Backcountry Skier Triggers Massive Avalanche Near Crested Butte

Avalanche

Colorado Backcountry Skier Triggers Massive Avalanche Near Crested Butte

Photo Credit:

Photo Credit: Chris Miller | Cover Photo: Ben Pritchett

[All photos courtesy of Crested Butte Avalanche Center]

Another close call in Colorado and another skier emerges from what appears to be a significant avalanche on Red Lady Bowl off Mount Emmons near Crested Butte, CO.

Find up-to-date avalanche forecasts here: Crested Butte Avalanche Center

According to a CBAC report, four skiers descended the slope near 12pm without incident. After they skied the bowl, a fifth and lone skier descended the bowl and triggered a slide that propagated across a large section of the face. The skier was lucky enough to ski into the tracked area, which avoided propagation.

“If we can collectively take home a few lessons and gain some experience from this accident, then we will be all the better as a backcountry community for it.” – Zach Guy, CBAC

In a thoughtful post, Zach Guy of CBAC went on to explain the takeaways from this close call and we advise everyone who frequents the backcountry to read his forecast discussion copied below.

Crested Butte Avalanche Center Report

Watched 4 skiers ski the bowl from my house via a telescope around 12:30 PM. It appears they didn’t encounter any stability issues.

Then watched a lone skier top out at 3:20 PM. He traversed another 50 or so yards east along the summit ridge past the entry point of the 4 earlier skiers, and then dropped in. He had made 10 or so turns, and then it happened; a majority of the bowl ripped out above him, almost edge to edge. Luckily at this point he had skied skier’s right of his drop in point, and had re-joined the 4 tracks from earlier.

It appeared he was ‘slightly’ caught in some sluff before skiing down to a narrow island of the slope that didn’t slide (that spot is very visible). He stopped in the middle of all the chaos as the slide ran on both sides of him, far down the slope where it eventually reconnected as it continued down the bowl.

The slide was well past him and he was skiing down when I lost sight of him. I lost sight of him, but counted 5 tracks (4 plus his) after the slide. So I ‘think’ he was OK. Close call.

***CBAC Note*** We are all very grateful that the swath of snow in the middle of the bowl did not slide in this incident. We want to dispel any beliefs that this commonly skied portion of the bowl is a “safety island.” Last December, a similar type of avalanche broke across the whole bowl.

Forecast Discussion

Anyone who has spent a lot of time traveling through or recreating in avalanche terrain has probably had a close call with avalanches at some point in their life.  I certainly have had numerous close calls (and I gave a talk about one of them recently at Avy Night).  We’re human, we’re not perfect. We are grateful that everyone is OK after yesterday’s close call on Red Lady, and take this as a cost-free learning opportunity.  This brings to mind a Rita Mae Brown quote, “Good judgment comes from experience and experience comes from bad judgment.”   If we can collectively take home a few lessons and gain some experience from this accident, then we will be all the better as a backcountry community for it.  Permit me to grab the drawing board for a moment to highlight some valuable lessons from a forecaster’s perspective.

1.)     Tracks on the slope don’t mean that it is stable, especially with persistent slabs.  Red Lady Bowl had four tracks down it before the 5th rider triggered the slide. It easily could have been the 3rd rider, or the 10th rider, or the 50th rider.  The culprit weak layers are buried several feet deep, and it takes a collapse of the layer to cause avalanche failure.  Weaknesses in the snowpack, or “trigger points,” becoming increasingly isolated as the slab becomes deeper and more uniform.  It can be challenging to identify those trigger points, and just because other folks descended a slope without finding one, it doesn’t mean that it is safe.

2.)    Persistent slabs can break quite wide and behave unusually.  This avalanche broke while the skier was about 10 turns down the slope, and showed impressive propagation.  The other skier triggered avalanche on Red Lady Bowl this year was remotely triggered.  Tricky stuff, and quite challenging to assess, especially in the alpine, where variable wind and snow loading make for uneven distribution of slabs and weak layers.

3.)    Traveling solo through avalanche terrain increases your vulnerability if something goes wrong.  Despite this highly visible path from town, CB Search and Rescue didn’t get to the trailhead until an hour after the slide, and even then, they weren’t launching a rescue until more information became available.  Had this avalanche resulted in a burial, it wouldn’t have ended well.  Having a partner watching from a safe location helps facilitate rescue responses quickly.

4.)    The last two close calls on Red Lady occurred the day that we lowered the danger from High to Considerable.  The majority of avalanche fatalities occur during Considerable danger.  We rate the avalanche danger based on our overall travel advice for a particular elevation band while considering the potential size, sensitivity, and distribution of avalanche problems.  Instabilities during Considerable danger may not be quite as glaring as you might encounter during a High danger day, which often lures people into more dangerous terrain.  Can you trigger a slide during moderate danger? Yes, of course.  On low danger? Yes.  But you are far more likely to get yourself in trouble during a Considerable day.

5.)  The island of safety.  We watch the travel habits on Red Lady and know that a lot of riders choose their descent near the ribbon of snow in the middle of the bowl that didn’t slide.  There are some terrain characteristics to that portion of the bowl that seem to reduce the frequency of some avalanches there, but it is definitely not a safe line. That same swath of snow got wiped out by a similar avalanche last December, and I’m sure Red Lady’s history has countless other slides where that terrain piece was wiped out.  The failure layer in this accident appears to be near the ground, so skier compaction would have minimal or no effect. Those layers were probably well buried before the first tracks went down that slope.  I can’t positively explain why that patch of snow didn’t rip out, but we’re all grateful it stayed put, and don’t count on it staying put next time.    

*Forecast Discussion by Zach Guy

 

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