The climber killed after a massive chunk of rock fell off the El Capitan monolith in Yosemite National Park was British, a park ranger has said.
Ranger Scott Gediman said that the man was with a British woman who was also seriously injured.
He said the two were hiking at the bottom of El Capitan's vertical face on their way to scale it when the sheet of rock estimated to be 130ft high and 65ft wide fell.
The rock fall was among seven that happened in the same general area during a four-hour period on Wednesday. Rescuers found no other victims.
The park records about 80 rock falls per year, though they are rarely fatal.
Experienced climbers of El Capitan said they have never seen a rock fall like the one "the size of an apartment building" that plunged down the vertical face.
"I've seen smaller avalanches and smaller falls before where you would just see a tiny dust cloud, this was covering a good portion of the rock in front of us," said John DeGrazio of YExplore Yosemite Adventures, who has led climbers scaling El Capitan for 12 years.
Mr DeGrazio said he had just guided a group to the top of El Capitan when the rock crashed to the ground, sending a large cloud of rock dust into the air. At least 30 climbers were on the wall of the 7,569ft monolith when the huge chunk of rock fell.
"It was more significant than anything I've seen before," Mr DeGrazio said.
Climbers are aware of the risks of the sport and that granite erosion takes place on El Capitan and in the Sierra Nevada mountain range, he said. They posted pictures on social media showing billowing white dust moments after the crash.
Canadian climber Peter Zabrok described the rock that fell as "white granite the size of an apartment building", adding that it suddenly peeled off the wall with no warning.
Mountaineers from around the world travel to the park in the Sierra Nevada to scale El Capitan's sheer face. Autumn is one of the peak seasons because the days are long and the weather is warm.
Ken Yager, president and founder of the Yosemite Climbing Association, said the piece that broke off "cratered and sent stuff mushrooming out in all directions".
Mr Zabrok said he saw a rescuer lowered by helicopter and "I believe he grabbed one survivor".
"It was done at tremendous peril to the rescuers because there were three subsequent rock falls that were all nearly as big and would have killed anybody at the base," he said.
Yosemite remained open after Wednesday's rock fall and other activities throughout the park were not affected, rangers said.
