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Once-In-A-Decade Avalanche Conditions In Aspen Area The Result Of Unusual Snow Patterns

Dec 28, 2020

Snowpack in the Roaring Fork Valley is particularly ripe for avalanches this year thanks to an abnormally dry spell. Colorado is already considered the nation’s most dangerous state for avalanches, and unstable snow across the state has already led to a number of deaths this year. 

The Roaring Fork Valley has not seen any avalanche deaths this season, but officials at the Colorado Avalanche Information Center said skiers have triggered slides in the upper Crystal River Valley near Sunlight Mountain and on Richmond Ridge near Aspen Mountain.

Brian Lazar, the center’s deputy director, said conditions like this haven’t happened since 2012.

 

“We’re looking at a snowpack that is really dangerous, and the kind of thing we see once every decade or so,” he said.

This year has been one of Colorado’s driest on record. A drought that began in the spring left large swaths of the Roaring Fork Valley in a state of “extreme drought,” the most severe level of classification on the U.S Drought Monitor.

The reason for this season’s weak snowpack has to do with the strange timing of snowfall through the early months, caused in part by that drought. 

 

 

A natural avalanche in the Castle Creek Drainage. Officials with the Colorado Avalanche Information Center said unusually dangerous snow means skiers of all experience levels should be on extra high alert.
Credit Colorado Avalanche Information Center

Early-season snow fell in October, then the area entered a long dry spell. With little new precipitation through November and part of December, that early-season snow was left thin and exposed to the cold for weeks on end.

“The end result is just very weak, cohesionless snow,” Lazar said. “That’s just a terrible foundation upon which to build the rest of the season’s snowpack.”

Then, right after the lifts started spinning in mid-December, consistent snowfall blanketed that weak base layer. Underneath the fresh powder, the leftovers from October are loose and prone  to falling apart. 

“You really don’t want to start off your snowpack by putting the weakest layer right at the bottom,” Lazar said. “It’s not how you build a building, and it’s not how you build a snowpack.”

Because those weak bottom layers are so pronounced, he said it will take “quite some time” for the snowpack to gain strength. More snowfall and warmer weather in the long run could help stabilize the area’s snow. 

Until then, skiers and riders need to stay on high alert in the backcountry. Lazar said even experienced users should be careful in areas they normally consider safe and look out for signs like audible collapsing and shooting cracks in the snow. 

“Even if you’ve been traveling in the backcountry for a while – your tried and true roots, the things that you would use in a normal year – may prove ineffective and actually dangerous this year because this is not a normal snowpack,” he said.

The pandemic is expected to continue to push skiers away from resorts and into the backcountry in record numbers, a trend that could mean a higher volume of inexperienced backcountry users venturing into risky terrain. Lazar said new and seasoned backcountry skiers alike should be on high alert.

“It should grab everyone’s attention that this is not a normal year, and you’ll need very careful terrain selection in order to stay safe this year,” he said.