One climber died and another was seriously injured after they fell about 1,000 feet from a peak at Denali National Park and Preserve in Alaska late on Thursday, officials said.

The roped climbers were ascending Mount Johnson, an 8,400-foot peak, along a route known as the Escalator, a steep and technical alpine climb on the peak’s southeast face.

The 5,000-foot route involves navigating steep rock, ice and snow, the National Park Service said in a statement.

Another climbing party witnessed the fall and alerted the Alaska Region Communication Center around 10:45 p.m. on Thursday. The climbers descended to the victims and confirmed that one climber had died.

“The responders dug a snow cave and attended to the surviving climber’s injuries throughout the night,” the statement said

A park high-altitude rescue helicopter and two mountaineering rangers from Talkeetna, a village at the base of Denali, responded early on Friday.

One of the rangers and the injured climber were flown to a flat glacier staging area, and then onto Talkeetna, where the patient was taken by a medical helicopter for further care.

The injured climber’s condition was not immediately known on Saturday, and neither climber has been publicly identified.

The rescue helicopter pilot returned to the site but was unable to recover the body of the climber who was killed because of poor weather conditions, the Park Service said. Rangers plan to return when the weather improves.