One member of a Japanese climbing team survived and four others are presumed dead after an avalanche swept them off a hill during their descent from Mount McKinley.

U.S. National Park Service officials say five people were traveling as one rope team early Thursday as part of a Miyagi Workers Alpine Federation expedition on the Alaska mountain.

Park Service spokeswoman Maureen McLaughlin said Hitoshi Ogi, 69, survived after falling 60 feet into a crevasse. He was able to climb out.

The others tumbled into the debris and haven’t been seen since. They are presumed dead by either snow burial or injuries.

Snowfall and wind have impeded a search for the climbers.

Hitoshi told Park Service employees that the climbers were descending the mountain when the avalanche began, McLaughlin said. They sped up, trying to get down the mountain faster, but the rope connecting them broke when the avalanche struck.

Hitoshi, the lowest person on the rope team, looked for the other four but couldn’t find them.

“He wasn’t sure of all the events,” McLaughlin said, adding that Hitoshi spoke through a translator and was exhausted.

The four missing climbers include Yoshiaki Kato, 64, Masako Suda, 50, Michiko Suzuki, 56, and Tamao Suzuki, 63.

There was new snow on the route, but the weather Thursday was calm, McLaughlin said.

“Where the avalanche occurred, the vast majority (of the new snow) was not on the main route,” McLaughlin said. “A small sliver of it was, and that’s what took them.”

Calling the avalanche “an unlucky, random event,” she said, “Avalanches do occur in this vicinity, but it’s not common.”