By Claire Cleveland / NewsBreak
Although spring brings warmer temperatures, it doesn’t mitigate Colorado’s avalanche danger.
So far this season, six people died in avalanches, and hazardous conditions persist in the backcountry.
How snowpack develops during the season determines avalanche conditions. Each storm produced different kinds of snow, and that snow is constantly changing. The surface may look like a uniform blanket of white, but dig beneath the surface, and you'll find layers built over time.
Currently, avalanches in Colorado are driven by a mid-winter long dry spell where the surface of the snow was exposed to cold temperatures that weakened the layer. Then came February’s snow, which added stiff snow on top of weaker snow.
“That's a recipe for an avalanche,” said Brian Lazar, the Colorado Avalanche Information Center deputy director. “It's not how you'd wanna build any structure. You wanna put your stronger materials on the bottom and the weaker materials on the top.”
Colorado avalanche deaths
Because Colorado's long-term seasonal average is six deaths, this spring could be deadly.
“The season's not over,” Lazar said. “We still have a good 6 to 8 weeks left of avalanche season. So we do have the potential for that number to go up, which would exceed our long-term average.”
This year’s conditions mirror last year in some ways. There was also a dry spell last year, but it was earlier in the season, which turned all of the snow on the ground into a weak layer. Then when snowfall returned, there was the same kind of strong snow over weak snow structure.
“What made a difference last year was the weak snow was more pronounced. It was more widespread across the Western U.S. and it was very continuous across the landscape,” said Lazar, who is also the central mountains lead forecaster. “When snow did finally return in the middle of the winter and we built slabs or cohesive pieces of snow on top of those weak layers, they were able to break over very wide and surprising distances.”
Avalanches were triggered from a thousand feet or more at the bottom of slopes, Lazar said.
At this time last year, 11 people had died in avalanches in Colorado. Because conditions remain treacherous, backcountry travelers need to stay vigilant.
“What we really wanna warn people about is that the snow is transitioning or moving toward spring. Currently, we're warning people about steep northerly and east facing slopes that are breaking on that drought weak layer,” Lazar said. “You can trigger avalanches from a distance and from below, so it's imperative that you have conservative terrain choices and give steep terrain wide buffers because avalanches are breaking in very hard to predict ways.”
Warm weather on the way, which could change the nature and flavor of avalanches in the coming weeks, Lazar said.
The best way to prepare for backcountry travel is to be familiar with avalanche forecasts, recognize the signs and conditions of avalanches, and carry the necessary emergency gear.
“If traveling in backcountry avalanche terrain is something you're interested in, getting the forecast needs to be followed by getting the appropriate gear for travel,” Lazar said.
“That at a minimum includes an avalanche transceiver, a probe pole and a shovel. And then you need to travel with partners who both have that equipment and know how to use it, which segues into kind of the third critical piece, which is getting some avalanche education.”
Lazar and the CAIC recommend a field-based avalanche course where participants learn to use the forecast to make trip plans based on conditions. They also train on how to use the rescue gear in case something goes wrong.