Sweetgrass Production's Valhalla, which is nominated for Movie of the Year at the POWDER Awards on Friday, is mind-bending in a lot of ways, with huge skiing, hallucinatory editing, and a story line straight out of the ’70s. The most mind-bending segment of all, however, is completely organic.

Skiers backflip between old-growth pines, stall on giant trees, air moss-covered stumps, and gap a 30-foot waterfall, all without any snow. It's essentially an urban segment in the forest in the dead of summer. Mike Brown, the producer at Sweetgrass Productions, developed the idea over two years. He was inspired by the image of snow-covered rainforests in Chile. "It just sparked this idea for combining these two contrasting worlds together," says Brown.

Brown and Sweetgrass director Ben Sturgulewski recruited a handful of skiers, including Karl Fostvedt and Eliel Hindert, and headed into the Mount Baker rainforest. Baker local Zack Giffin, the main athlete in the segment, suggested the location. His extensive understanding of the terrain and experience as both a carpenter and director of the Baker park crew made him an invaluable member of the team.

The segment was filmed over the course of two years, with one three-week expedition into the rainforest in June 2012 and another in late July 2013. While in the woods, everyone—cameramen, interns, and athletes—worked together to visualize, build, hit, and film features. Setting up for one shot could take up to a week, after building in-runs, landings, and jumps and driving truckloads of snow in from the nearby glacier. They would hit the feature until the snow melted, break it down immediately, and begin building the next one. "Everything had to line up perfectly for the shot to happen," says Brown, who reported time constraints and construction as the two biggest challenges. "There wasn't really time to be making a mistake and redoing things."

The crew learned a lot the first year. Cool early-summer weather kept snow frozen, but overcast days eliminated the sunlight needed for filming. The second foray into the rainforest proved smoother than the first. They came back to friendlier skies, with a few new athletes, new ideas, and a better understanding of what they were getting themselves into. Filming wrapped in early August, just a month before the film premiered to awestruck audiences in Denver.

VIDEO: POWDER TV takes you behind the scenes with Sweetgrass to learn more about the work that went into producing the forest segment.