Three climbers on Alaska’s Mount McKinley who fell near a treacherous pass on North America’s tallest peak have died, a Latvian mountaineering group announced Friday. A fourth climber was rescued.

The four were members of a Latvian mountaineering expedition, the group said. They were part of a seven-person team traversing a route known for its exposed sections — where many injuries and deaths have occurred over the years — when they fell Wednesday, the National Park Service has said.

McKinley stands at about 20,310 feet, and the climber who was rescued was brought off the mountain from about 17,200 feet by Denali National Park and Preserve search and rescue personnel late Thursday afternoon. A long line from a helicopter was used in the rescue because the terrain and conditions prevented the helicopter from landing, the park service said Friday. The climber was later airlifted to a hospital.

The fall happened during the climb near Denali Pass, which is about 18,200 feet, the park service said. It provided few other details. The three others in the climbing group helped with the rescue work and started experiencing “declining physical conditions,” the park service said. Crews evacuated them from the mountain Friday.

The group was on the West Buttress route, the most popular path to the summit. It’s known for crevasses, steep ice and exposed ridges.

Over the years, many climbing injuries and deaths have occurred on the traverse between an area known as high camp at around 17,200 feet and Denali Pass, mainly resulting from unprotected falls, according to the park. Most of the deaths along the pass have happened while climbers are descending.

Park rangers and mountain guides install and maintain snow pickets — which are used to help build anchors for extra protection on areas like steep slopes — between the high camp and Denali Pass, the park has said. That area also is known as the Autobahn, a snow and ice slope that can be marked by conditions ranging from deep snow carrying avalanche risk to hard ice, the agency said.

Climbers can put in their own pickets if needed, but “you might have to bash it in through very, very dense snow and ice even,” said climber Clint Helander, who has summitted McKinley and been on the mountain numerous times.

Intense glaciation, rapid weather changes, altitude and the sheer scale of the peak make climbing McKinley “a huge undertaking,” he said. Climbers also must carry a significant amount of gear for what can be long expeditions, he said.

“It’s immensely easy for something to happen and turn an otherwise straightforward trip into an epic,” Helander said.

Only about 1,000 to 1,200 climbers attempt to reach the top of Mount McKinley each year, mostly during May and June. The trip usually takes about 17 days, and less than half made it to the summit last year, according to park statistics.

More than 130 people have died on the mountain in the history of the park, including two deaths last year, according to park statistics. In 2012, four climbers from Japan were killed after a shallow avalanche pushed them into a crevasse.

There were 516 climbers on the mountain as of Thursday, said Scott Carr, a park service spokesperson.

Two others climbers who were not with the group that fell were evacuated from the mountain by helicopter Wednesday, according to the park service.