Storms sweeping across the Rocky Mountains this winter have caused the highest avalanche danger since the ratings started in 1973. More than 3,000 avalanches have already taken place in Colorado alone, and they’re unusually large.

The White River National Forest lies just outside of Aspen. Part of the forest is known as Highlands Ridge.

The valley below that ridge is now buried because of an avalanche. The snow is deep enough that treetops barely poke out. The trees that aren’t buried haven’t fared much better.

“Old 50-foot, 60-foot, 70-foot trees have been snapped like toothpicks,” says Zachary Paris, property manager for the house at the bottom of two new avalanche paths below the ridge.

A one-mile-long section of Highlands Ridge collapsed under its own weight earlier this month, sending a cascade of snow and debris onto the valley floor below.

“We’re probably standing on a 20, 30-foot pile right now,” says Paris.

More avalanches, larger avalanches

The Colorado Avalanche Information Center estimates that the Highlands Ridge slide could be the largest in almost 300 years and that it reached speeds of over 110 miles per hour.

“We’re seeing much more of these large and destructive avalanches,” says Brian Lazar, a deputy director of the center.

Avalanches are rated on a scale out of 1 to 5. The Highlands Ridge snow slide was a 4.5. It’s just one of the hundreds of record-breaking slides triggered in Colorado’s high country so far this year.

“We saw more in the first ten days of March than we’d typically see in a five year period”, says Lazar.

His research suggests that, as the climate warms, wet snow avalanches like those he’s seeing now could start two to four weeks earlier than normal. That means a longer avalanche season.

“We’re certainly starting to see weather patterns which are intimately tied to avalanche activity that is different than what we’ve seen in past years,” says Lazar.

Longer avalanche season

A longer season with warmer weather means an uptick in slides is likely, which makes controlling avalanches in ski areas like Aspen difficult.

Aspen Ski Patrol uses charges — little bombs — to trigger slides in controlled conditions to prevent catastrophic and deadly avalanches. These explosions can be heard from downtown Aspen after a big snow storm.

Aspen Ski Patrol doesn’t release specifics about how many blasts it sets off for avalanche control, but it does say it’s increased the number of charges this season and spent more time mitigating avalanches.

The patrol is in regular contact with Brian Lazar’s team at the Colorado Avalanche Information Center because he gives the patrol the go-ahead to set off these controlled slides.

Avalanche season isn’t over. According to Lazar, as temperatures go up, so can avalanche danger

He says when “things start to melt, we can see a spike in wet avalanche activity.”

That means Colorado can expect to see more slides in a what has already been a record-breaking season.