On the outskirts of the Tsirku glacier lies an otherworldly peak named Corrugated, after the physics-defying spines running down its face. It had been ridden just once before last winter, when Sam Anthamatten, Hadley Hammer, and Ralph Backstrom traveled to the remote zone where British Columbia, the Yukon, and Alaska converge.

Documented in a new series, Tsirku, from Sherpas Cinema and North Face, the team’s journey began with dreamy heli-skiing courtesy of the new Yukon Helicopter Guides in Haines, Alaska.

“The beautiful thing is every descent is a first descent,” Sam Anthamatten says of their first forays into the Saint Elias Mountains: dramatic lines through steep granite spires.

After exploring the nearby terrain by air, Anthamatten, Hammer, and Backstrom prepared for a 60-kilometer snowmobile journey from Haines Pass to the Tsirku glacier. The treacherous route took the skiers and hundreds of pounds of gear through avalanche terrain and across crevasse-scarred glaciers. They spent a week caching supplies and route planning before making the arduous journey.

When the team finally made it to Tsirku, they were struck by their objective.

“I’ve never seen anything like that face,” Backstrom says. “It’s indescribable.”

The massive, tightly packed spines hold more snow than seems possible, given how steep the face is. Looming over their camp, in perfect relief thanks to crystal-clear weather, Corrugated held promise but huge potential for failure, too.

While beautiful to watch, spine skiing is incredibly technical. Evading slough, managing speed, and maintaining orientation on the broad face are incredibly difficult. Once they reached the summit, the athletes also had to navigate a massive, fragile cornice spanning the entire ridge.

Anthamatten, an experienced ski mountaineer and guide, developed an elaborate solution involving a sketchy rappel and a couple very close calls to get them onto the face. Despite the challenges, the team successfully laid down three more descents of Corrugated.

All told, that one steep, deep line had the three of them in the Yukon for an entire month. And yet, after achieving their hard-won objective, Hammer declares, “It makes me just want to come back more and more. For me, I just never want to go back to civilization.”