The ice fell from Ruth Glacier, hitting the two-man rope team Thursday morning, the park service said in a release.
The 31-year-old male survivor, from Logan, Utah, was knocked out by the falling ice. When he regained consciousness, he saw that his climbing partner, a 32-year-old man from Rigby, Idaho, had been killed.
The Utah climber then alerted park officials using an InReach satellite communication device about an hour after the incident.
“Despite significant injuries, the surviving climber managed to move to a location outside of the debris zone to await rescue,” the release said.
Rangers rescued him by helicopter and he was taken by air ambulance for further care.
Denali National Park and Preserve is about 240 miles north of Anchorage. It includes North America’s highest peak, Denali, formerly known as Mount McKinley.