In the midst of a winter storm on Friday, avalanche conditions were deemed dangerous from Craig to the New Mexico border, the length of the Western Slope.
In the aftermath of the storm, from Feb. 14 to Feb. 16, at least 55 reports of avalanches in the San Juan Mountains from people who either saw or started one, according to the Colorado Avalanche Information Center.
In the past week across the state, there’s been 156 reported avalanches, said Mike Cooperstein, the Northern Mountains regional manager at the Colorado Avalanche Information Center.
As it warms up and the skies clear after a big storm, Cooperstein said they see a lot of accidents.
“Be on guard for a little bit, and don’t get too excited when the sun comes out,” he said.
Over the weekend, backcountry skiers caused a majority of the avalanches.
Nobody was injured, though “secondhand parking lot conversations suggest a party triggered an avalanche … while skinning and had been buried up to their knees,” a report by CAIC staff reads.
That happened near Silverton in the Cement Creek Area, where “avalanches appeared limited to storm snow,” the report says.
There’s “a lot of new snow on a bunch of weird surfaces,” CAIC forecaster Jeff Davis wrote on Feb. 14. “Cold, weak snow lurks in the middle and bottom of the snowpack.”
Davis reported three avalanches in the Northern San Juans: One was natural on Feb. 13, and two were intentionally caused by skiers on Feb. 14.
Skiers intentionally cause avalanches to see how sensitive things are by walking or skiing across the top, Cooperstein said.
“It takes a lot of skill, time and practice in the mountains to know places that are safe to do that,” Cooperstein said. “More people do it than they should.”
Most of the avalanches reported this weekend earned a D1 rating, which means they’re “relatively harmless to people.”
A handful received a D2 rating, which “could bury, injure or kill a person.”
Two avalanches that received such a rating happened the day of the storm, Feb. 14, in the Southern San Juan Mountains.
One was attributed to persistent slab, which is a “release of a cohesive layer of snow (a slab), when the bond to an underlying persistent weak layer breaks,” according to avalanche.org.
The other was a storm slab problem, which is a “release of a soft cohesive layer (a slab) of new snow which breaks within the storm snow or on the old snow surface,” according to the Sierra Avalanche Center.
Most of the avalanches this weekend were attributed to storm slab problems.
“It was a gift to get into the La Platas after a solid bout of moisture,” Elliot Baglini wrote on Feb. 15. “Found 50 centimeters of supportable, top-shelf schmoo over dirt on south aspects … we felt consistent collapses, although no tree-shakers.”
The most severe avalanche recorded in the San Juan Mountains this weekend was on Feb. 14 near Crater Lake. It received a D 2.5 rating, which is at the high end of an already lethal class.
Near Molas Pass, skiers “gave up when we realized anything steep enough to ski was steep enough to slide,” Rob Suminsby wrote on Feb. 15.
One “relatively harmless” avalanche was triggered in the Southern San Juans by a snowmobiler on Feb. 16.
“I remotely triggered an avalanche from around 250 ft away while skiing down a ridgeline,” CAIC Forecaster Krista Beyer wrote on Feb. 16. “The avalanche appears to have failed on prestorm weak surfaces and gouged into old snow.”
“Steep gully walls and road cuts remain reactive to human trigger from above and from below,” said Beyer.
As of Feb. 17, the San Juan Mountains are at a “considerable” avalanche warning. In Northern Colorado, much of the mountains remain at a “high” warning level.
“Heavy snow and strong winds dramatically changed avalanche conditions,” according to CAIC’s website. “You can easily trigger large, deadly avalanches throughout Presidents Day weekend.”
Backcountry users are encouraged to stick to slopes less than 30 degrees in steepness.
“Westerly wind continues drifting snow, building slabs, and stiffening slopes, making it easier for you to trigger avalanches,” CAIC warns. “We could even see some natural avalanche activity with continued loading on Monday.”
