DULUTH — There was buzz among winter surfers in early January, predictions that an incoming storm could deliver epic waves along the North Shore of Lake Superior.

They were right. Fifteen-foot waves — the kind that draw superlatives from the pros — rolled in midweek and dozens of cars, some topped with surfboards, lined the road near a favorite spot at Stoney Point.

"These surfers are all mini-meteorologists," said Ian Planchon, a filmmaker who has spent the past three years embedded in the Lake Superior surfing community.

He was just more than a month out from the release of "Freshwater," a documentary directed by Planchon and Lynn Melling, which started as a look at winter surf enthusiasts — some of whom travel hundreds of miles when the forecast looks ripe for big waves. While they were filming, the subject broadened to include other facets of one of the world's largest freshwater lakes: the students and scientists who study it, the visitors who are drawn to it and the people who have been saved by it.

The 50-minute film, along with the last-minute additions of footage, premieres at 7 p.m. Saturday at the NorShor Theatre in Duluth. All proceeds go to the Large Lakes Observatory at the University of Minnesota Duluth, which is featured in the movie. After the screening, the filmmakers are planning to take the movie to festivals and find a distributor for it.

On that frigid 5-degree day in January, Planchon hiked through the woods to a clearing with a view of the bodies bobbing in the water and occasionally catching waves — among them pro surfer Ben Gravy of Florida, who later posted to Instagram that he experienced "the swell of the century in Minnesota."

"We weren't supposed to be here today — then every surfer here posted about it," Planchon said. He had already taken what he thought were the final shots for the movie, but he couldn't resist shooting this spectacular scene.

From water to people

Planchon and the crew from 515 Productions had set out in 2019 to make a movie about the Lake Superior surf scene. But because travel and in-person interviews were complicated during the pandemic, the team had time to consider looking at the subject with a wider lens: What is it about Lake Superior that keeps people coming back?

One answer: "It's my church," Vonnie Wilkie says in the movie. She and her husband, Erik Wilkie, regularly surf on the big lake.

"It's a pretty hidden idea still," surfer Amy Verby says of winter surfing. She goes on to list how she prepares for it: a thick wetsuit, gloves, hood and booties, then Vaseline to keep her face from freezing and hot water to thaw her zipper.

The film also includes footage aboard Blue Heron, the University of Minnesota Duluth's research vessel, and lakeside interviews with Jay Austin, a professor of physics and astronomy, and Cody Sheik, a geomicrobiologist.

Christian Dalbec, once a chronic alcoholic, is the film's final chapter. About a decade ago, Dalbec started taking photos of the lake in an effort to stay sober. Since then, he's continued to find fresh ways to view Lake Superior, whether he's shooting from the shore or slipping into scuba gear to capture the ever-changing underwater scene. The lake, he says in the movie, has kept him alive.

The thread that runs through the movie is shown in slow motion, with wicked waves folding in on themselves and the power of the water hitting the shore.

"Lake Superior is the character," Planchon said. "How people connect is the story we're trying to tell."