In 1997, Mark Bosse worked as a car mechanic at the GM Chrysler Subaru dealership in Montrose, Colorado. On one mid-winter powder day, he called in sick, drove his copper-colored 1991 Subaru Legacy Wagon 90 minutes to Telluride Ski Resort, and loaded Lift 7. By the time his ski tips hit snow, he'd decided to trade in his garage gig for a mountain job—and more ski days.

Soon, Bosse was a Telluride lift mechanic, skiing 80 days each winter. Then, his chairlift epiphany led to an innovation that is reshaping resort operations across Colorado: the Bosse Roller, a $37,000 three-wheeled machine that weighs 2,200 pounds and is used in high alpine terrain to disrupt weak layers in early season snowpack. Telluride, Monarch, Winter Park, Copper, and Arapahoe Basin currently use the roller, where a more stable snowpack can mean terrain opens faster, especially in low snow years.

Not that Bosse had a master plan. He just wanted to ski more. His father, a teacher, and his mother, a nurse, raised him in Montrose and put him on skis at age 4. Bosse's first job was repairing lawnmower and chainsaw engines; after high school, he enrolled in a GM training program. That brought him to the dealership, where he specialized in transmissions. "If I see a niche, I take it," he says. "I love to build stuff, but my favorite is things that don't exist. Or if there's a particular need for something and I get to visualize and build it."

The Bosse Roller in action at Arapahoe Basin, Colorado. PHOTO: Ryan Evancyzk

That mentality fit well at a ski resort. When lift parts failed, and service calls or shipments from Europe would take too long or cost too much, Bosse fabricated new pieces. To spot his work, looked closely at bull wheels and lift towers for metal pieces dipped in signature purple paint. He also fixed fleet vehicles, groomers, and snow cats. Plus, he designed and built everything from retail display stands to the bridge and staircase that lead to Gold Hill Chutes 9 and 10 in Telluride's prized high-alpine terrain.

But ski patrol eventually asked Bosse to tackle another challenge. In the Colorado high country, first snow often arrives in October or November. "When you have early season snowfall, you develop weak base layers," says Colorado Avalanche Information Center Director Ethan Greene. "Ski patrollers break them up so that when more snow falls on top you don't have a uniform layer of weak snow underneath." Traditional disruption methods include boot packing, ski cutting, skier traffic, and explosives. They're used early and often, because left intact, persistent weak layers provide a planar surface that allows avalanches to propagate.

Telluride had developed another compaction tool: a concrete-filled culvert with spindles at each end that winch cats rolled down avalanche-prone slopes. But the gravity-fed device pushed snow downhill, got stuck in its own rut, and didn't provide enough ground pressure to break through hard slabs. They added tires on a steel frame, but these glitches persisted. So in 2010, they asked Bosse for improvements.

His first idea: steering. A third, articulating wheel, operated by remote control while a winch cat lowered the roller downslope. The first test run down Gold Hill Chute 4 proved successful. But on the second pass, rocks tore the tongue off and sent the roller tumbling 1,000 feet. Bosse cut his design to pieces for helicopter extraction, and back in the shop, he rebuilt with hydraulics to improve steering. Before long, the Bosse Roller was in regular use on Telluride steeps like Electric, Dynamo, and Little Rose. Now, rather than eliminate weak layers by triggering slides that scrape these pitches clean, the roller stabilizes and conserves snowpack.

Since Bosse completed the Telluride project as a subcontractor, he could market to other resorts through his company, Unique Fabrications. In 2013, Monarch needed a roller capable of busting through cornices in their cat skiing terrain. So Bosse added a Honda gas motor to make a self-driving machine. Winter Park acquired a roller in 2014 for the Cirque, a 399-acre bowl with chutes that range from 32 to 45 degrees.

With the Bosse Roller compacting snow layers, no bootpackers are required. PHOTO: Mark Bosse

Next up: Arapahoe Basin. The roller operates in Montezuma Bowl and the Pallavicini Lift zone; ski patrollers are considering use on lower-angle, south-facing slopes where a consolidated snowpack might slow the spring melt. "In our high alpine environment, wind is treacherous. It can scrape a slope clean," says snow safety director Ryan Evanczyk. "It behooves us to step on every snowflake we can. The roller helps with that." Copper followed, "It's like the biggest, coolest remote control toy you can imagine," says ski patrol manager Hagen Lyle. His patrollers use the roller in Spaulding Bowl and on the Drainpipe trail.

The roller doesn't replace traditional compaction methods—it simply accelerates the process. "In a day of rolling, myself and a winch cat operator can get done what it takes eight to 10 patrollers to do in a week," says Winter Park snow safety coordinator Mike Schneider. "The time and safety savings are huge." That's because the less eight-hour days boot-packers put in, the lower the chances of a knee or hand injury from a slip on snow-covered talus. And if patrollers do not observe persistent weak layers as they dig inbounds pits throughout the season, there's no reason to put people on a loaded slope to drop charges during control work.

Bosse says he's in talks with two more resorts outside Colorado, and one in Canada.

However, the roller is not a universal fix. Winch cat access is required. That rules out Aspen's Highland Bowl, where ski patrol recruits members of the public to bootpack in exchange for a season's pass. And time-tested methods offer benefits, too. "A roller can't tell you there's a 5-centimeter melt-freeze crust 20 centimeters off the ground, but you'll know if you're walking around in the snow day in and day out," says Aspen Highlands ski patroller Mike Spayd. A similar program exists at Copper, which still uses boot-packers to compact snow in complex terrain the roller can't access.

And Bosse's clients caution the roller won't eliminate all natural hazards. "Our goal is to get the terrain open for people and get it to them as soon as possible to have fun," says Copper's Lyle. "But it's still avalanche terrain and there's nothing we can do to make avalanche terrain 100 percent certain or safe."

Still, he agrees Bosse's creation adds a valuable tool to the snow safety arsenal. And so Bosse continues to manufacture rollers at his home in Norwood, a 45-minute drive northwest of Telluride. His headquarters at the 35-acre property: a 24- by 30-foot workshop filled with lathes, mills, and tools. Assembly takes place outside.

Twenty-two years after he hired on at Telluride, Bosse plans to stay put, driving to and from the mountain in that same Subaru. "That's where I do most of my daydreaming. A vision will just pop into my head and I'll see exactly what a part or a project is supposed to look like," he says. "Without the commute, I'd have to wander aimlessly around the countryside." And that's no place for a skier.