On a typical winter day in Flagstaff, Arizona, ultrarunner Rob Krar makes his way up from the base of the Arizona Snowbowl at 9,300 feet, with a headlamp, gloves, and breathable layers of clothes.
But this is no run. Instead, it’s skis and skins, poles and backpack, for a two-hour session of ski mountaineering, Krar’s physical activity of choice in the winter. He labors up 2,200 feet of vertical elevation gain, the sun setting behind him, painting the sky radiant pink and orange.
He’s the two-time Western States Endurance Run champion, but Krar doesn’t touch his running shoes for two months out of each year. Instead, he opts for an activity that revitalizes his mind and body, both worn down from a long running season.
“Skimo is such a cornerstone of where I am today,” he says.
“Skimo” is short for ski mountaineering. Instead of riding a ski lift up the slope, athletes cover the bottom of their skis in skins, which provide tread to prevent them from slipping backward. Then they climb to the summit. At the top, they remove the skins and ski back down, legs still raging with lactic acid from the trip up.
“The biggest thing for me is knowing that through the offseason, I’m really maintaining my fitness, if not improving it, with absolutely zero pounding on my legs,” Krar says. “It’s a mental recovery after a long season. And it’s a different burn after a year of running.”
The sport is gaining traction among trail runners for physical and psychological reasons, and it’s a way to avoid the treadmill when the weather turns harsh. The benefits for runners are many: It builds aerobic fitness and it increases strength in the upper body, hip flexors, and glutes without straining joints. Many athletes emerge from the winter with more power and endurance than when the running season ended.
“I’m a little afraid it’s about to become the new big thing,” says Stephanie Howe, who competed in Nordic skiing in college and won Western States in 2014. “I think with social media everyone just keeps an eye on what everyone’s doing now.”
Part of the allure comes from the inherent lack of structure. Howe and Krar don’t plan and complete workouts, and even the amount of time they commit each session is flexible.
“I don’t go out there with a goal of, ‘Oh, I’m going to do so much vertical,’ or, ‘Oh, I’m going to be out there for this many hours,’ “ Howe says. “It’s more like: ‘We’re going to go do this mountain, or do three laps on this place.’ I like to keep it less defined.”
Fitting in a skimo session takes a bit more forethought than going for a run. Every ski mountain has its own policies regarding times that skimo activities are allowed. For many areas, it’s before and after the lifts close. Stevie Kremer, a member of the Salomon trail-running team and a second grade teacher in Crested Butte, Colorado, hits the slope in the early morning and evenings.
“A typical day for me is waking up at 5 a.m., heading to the ski area with my ski gear, and skinning up the hill,” Kremer says. “I am then down around 6:30 a.m., shower and head to work. Typically, I try to do this at least once per day, but sometimes two times. I’ll try to head up after school, too.”
For the more adventurous and experienced, skimo can also take place in the backcountry, where no ski slopes exist. Be prepared by knowing what you’re getting into and if it will require additional gear like ice axes and crampons. Don’t ever trek into the backcountry without taking an avalanche training course.
“You can just go off into the woods, which is kind of what trail running is like for me,” Howe says. “As I’ve become more of a runner, I make sure to make a point to do other activities. I think it’s important for longevity in the sport and for keeping me balanced. I don’t need to run every single day, and especially in the offseason.”
Going Up?
Before taking to the snow-covered mountains, a few points to consider:
Gear
Running gear is simple. Skimo gear is not. The lighter your gear, the more efficient the climbing will be (and the more expensive your setup will be). Skis tend to be narrower than regular alpine skis. They are also fitted with AT bindings, which allow you to lift your heel on the ascent, then lock in for the downhill. Boots have an “unlock mode” that frees the movement of the ankle and lower leg for the climb. Skins are strips that attach to the bottom of the skis to provide traction on the way up—you remove them before heading down.
A midrange set of gear starts around $1,500. Packages can run upward of $3,000 to $4,000 for top-level, lightweight racing equipment.
Skills
If you’re an inexperienced downhill skier, master the basics first. Take a lesson on the beginner slope and learn how to stop and turn going downhill before you find yourself on a summit, unsure of how to get down without hurting yourself.
Mountain Policies
Many mountains limit access to times before the mountain opens or after operations cease. Some resorts—including Okemo Mountain Resort in Vermont—allow uphill travel during the day, but limit terrain to beginner and intermediate trails, asking that skiers stay along the edge of trails and maintain a single-file line.
Some mountains charge an access fee. At Crested Butte in Colorado, it’s $10 per day, or $100 per season.
Racing
For those who need to satisfy competitive juices during the offseason, plenty of resorts plan skimo races these days. For opportunities, visit the U.S. Ski Mountaineering Association at ussma.org/events.
