Many people meet Dale Atkins for the first time on their worst days—ice climbers who are stranded and injured, skiers that have been swallowed by an avalanche. Atkins, a skilled mountaineer as well as a climatologist and former weather and avalanche forecaster, is one of the experts on Colorado’s Alpine Rescue Team that local sheriffs call to the rescue.
In some ways, planning for and executing those rescues is becoming more complicated because of climate change. Weather fueled by climate change can elevate hazards on the mountain, whether through weird winter rain, blizzards, droughts, or summer wildfires. Each extreme impacts the landscape with a potentially fatal danger. And faced with such unpredictability, experts can’t shake the fear that their work is shifting away from recreational rescues toward disaster response.
“We know that our summers are getting longer and drier and warmer—and our winters are getting shorter and drier and warmer, too.” says Atkins, who has been part of the Alpine Rescue Team for 50 years. “But what we’re also seeing is the amplitude of the storms. We’re seeing the extremes more often. For us in mountain rescue, it’s those big storms that can cause us a lot of hard work.”
Despite a recent string of unseasonably hot and dry years, last winter blanketed the western US and Canada with historic snowfall. Colorado officials reported that 5,813 total avalanches caught 122 people and killed 11, the second-most deaths since records began in 1951. The National Oceanic and Atmospheric Administration, or NOAA, predicts a warmer and drier year this winter into 2024.
That could be both a good thing and a bad thing. One of the most lethal hazards in a winter landscape might come as a surprise: rain. As average winter temperatures creep up, rain falls higher up the mountain, where snow normally falls. These “rain on snow” events occur more at the start of winter and early spring, according to Ty Brandt, a snow hydrometeorologist with the Scripps’ Center for Western Weather and Water Extremes. Climate change could bring more.
The quandary here runs deeper than slushy snow and warm ski days. In certain alpine conditions, rainfall percolates down the upper layers of snowpack, and can refreeze and trigger avalanches. Pinning down precisely when and why each happens is still an open question, Brandt says.
Wet avalanches also carry a unique threat, since they behave differently. A person buried in a typical avalanche can survive about 15 minutes thanks to air pockets around the dry powder. Denser wet slab avalanches don’t provide that luxury. The rescue needs to happen faster.
“We are seeing changes in the composition of the snowpack, such as the presence of persistent slab avalanche problems, becoming more frequent in maritime snowpacks in recent years,” writes Jen Reddy of the American Avalanche Association in an email to WIRED. “And wet slab activity, the past few seasons, has started earlier in the spring.”
Blunt trauma also becomes a risk factor with rain on snow, according to a 2021 study of mountain emergency medicine. Rain creates a rock hard “crust” in the snow pack, raising the risk that people take a fall, or slip and hit a tree or rock. And a rain crust is easy to overlook when it’s concealed by a fine layer of powder.
Rain on snow occurs more in maritime conditions, like on Alaska’s coast or in Washington state’s Cascade Range, but Atkins suspects wet avalanches will also happen more in Colorado’s early spring than previously. And as hotter summers bake away alpine ice, once-permanent glaciers reveal large unnavigable crevasses and areas prone to rockslide. “We are losing our ‘highways’ to quickly access and evacuate injured people, which makes evacuations much more difficult and dangerous,” Atkins says of the vanishing ice and snow.
Unseasonably warm sunny days can also thaw the snowpack, only for it to freeze again when temperatures drop. Snow turns to water, water to ice. “Every two or three winters in Southern California, people out hiking take these really long, sometimes fatal falls on this hard ice,” Atkins says. Some hikers buy attachments for their shoes like microspikes for ice, which Atkins believes are convenient but often insufficient because the spikes are too short. “The trail is literally like a luge run.”
What amplifies the issue of hazardous terrain is who is on it. Ski resorts report more visitors than ever. That includes more people traversing the terrain and driving icy roads for the first time. Reddy notices more people spending their days off-piste in the backcountry too. Skiers and snowboarders flock there to avoid crowds. Mapping technology and avalanche forecasting systems have made the backcountry safer in certain ways, but that’s a double-edged sword: “Technology like this is a great tool to promote access to the winter outdoors, but it is not a substitute for practical field experience and educated decisionmaking," she says.
Atkins agrees that forecasts are only as good as your ability to use them. “There’s no reason to be surprised by a storm anymore,” Atkins says, but it’s tough to really predict how it will affect the mountain: “A forecast that might be right for a mountain range can be wrong for a specific mountain summit or a valley. People have to be ready for that.”
And for bigger storms more common with climate change, the severity can catch even the most experienced adventurers off guard. “It’s not out of the ordinary for a range to get 30, 40, 50 inches of snow in a single storm,” Atkins says. “What’s become very unusual and more frequent are the storms that are covering entire mountain ranges or large swaths of the state.” Such a storm swept through Colorado in 2019 and triggered record-setting avalanches, including one that was one-mile wide.
These storms mean that it’s not just skiers and climbers who need assistance, but often entire communities. Colorado’s Alpine Rescue Team also helps residents trapped by snow and floods.
“The problem with climate is that we’re heading into a period where the past is not necessarily reflective of the present or the future,” says Brandt. Weather and climate are changing, but so too is the terrain. Avalanches level trees like toothpicks. Summer wildfires flatten forests beyond recognition. Landscapes are changing at a rapid clip, so the way that experts traverse them will shift—“and it’s going to shift in ways that are very unknown.”
In December, ski resorts in the Pacific Northwest like Crystal Mountain reopened for the season with fresh snow. Then, on December 6, an atmospheric river dumped 6 inches of rain across the Washington ski area. The snow washed away and Crystal closed again. “Atmospheric rivers have been bringing havoc to our mountains for eons. But maybe we’re starting to see more of them,” Atkins says.
He and other rescuers who spoke with WIRED fear what trouble unusual storms could create as the backcountry lures more people to enjoy pristine powder and scant crowds. In 2018, a storm rolled through Jones Pass outside of Denver, trapping an experienced skier in howling 60-mph wind, snow, and sub-zero temperatures. The skier took a severe fall in the whiteout. “It was his favorite playground,” Atkins says. “He was in an area that he probably knew quite well. But that one day the conditions were too much, and sadly, it cost him his life.”
