'Free Solo' director recounts his near-death experience getting caught in an avalanche for National Geographic series that explores what happens when outdoor adventures go horribly wrong

• National Geographic's new series recounts terrifying moments when outdoor adventures went horribly wrong.
• Narrated by climber and filmmaker Jimmy Chin, the series shows athletes at their most vulnerable.

A backcountry snowboarder caught in an avalanche on a pristine Alaskan slope. A pair of explorers dodging polar bears while traversing the Canadian arctic. A professional climber experiencing a heart attack at 20,000 feet elevation in the Himalayas.

These are just some of the terrifying moments featured in the new National Geographic series "Edge of the Unknown With Jimmy Chin," which tells the insane stories of elite adventure athletes when things went disastrously wrong.

The series is the latest project from Chin, a professional skier, climber, and filmmaker, and his wife, E. Chai Vasarhelyi. The directing duo is best known for their feature-length documentaries like "Meru," "The Rescue," and "Free Solo," which won the Academy Award for Best Documentary Feature.

"I think of it as the greatest stories you haven't heard, because if you look at the roster, it's literally the greatest of the great, the most elite athletes in each of their respective sports or disciplines," Chin said in an interview with Insider.

But rather than tell the stories of the athlete's accomplishments, the 10-episode series focuses on some of their most vulnerable moments. One episode features big mountain skier Angel Collinson taking a 1,000-foot fall in Alaska. Another recounts a climb made by professional climber Alex Honnold in Morocco without the protection of ropes. One episode shows how big wave surfer Justine Dupont got crushed by a massive swell in Hawaii.

The series has the breathtaking shots one expects from stories about outdoor athletes, but it's also scary at times and emotional as the athletes describe their accidents — often alongside harrowing footage — the regret and embarrassment experienced over mistakes they made, and how they moved forward.

"This is real. This isn't some glossy version of 'We're pro athletes, we're always psyched, we're never scared,'" Chin, who also serves as narrator of the series, said. "It's rad because it's not that."

Fans tend to see professional climbers, snowboarders, and surfers in their coolest and most triumphant moments — after they've just won a competition, in slick footage sporting their sponsors' gear, and in glorious photos and videos shared on their Instagram feeds.

But Chin wanted to remind the audience that elite athletes aren't superheroes and highlight some of the mental challenges that come with doing these sports.

"There's so much external pressure and internal pressure to be perfect and infallible and yet we're all humans," Chin said.

"I think it's even more inspiring to hear how these athletes have come out of these really difficult moments than when they're performing at their peak," he continued. "It's an access point for people to understand what these athletes and people are really like."

Chin himself is the subject of one of the episodes. He tells the story of the time he was nearly buried alive after getting caught in a class-four avalanche while skiing in his home range, Wyoming's Tetons.

"I felt like if I was asking everybody else to lay it on the table, then it was only fair if I put it out there as well," Chin explained. He cited the episode in which whitewater kayaker Gerd Serrasolses recounts nearly drowning after tumbling over a 50-foot waterfall — and the accompanying GoPro footage that shows him on the verge of death.

"I was like, 'Okay I can't ask people to do that unless I'm willing to do the same," he said.

"Edge of the Unknown with Jimmy Chin" premieres September 5 on National Geographic. All 10 episodes will be available for streaming on September 7 on Disney+.