"I saw a piece of rock, white granite the size of an apartment building, at least 100 feet by 100 feet, suddenly just come peeling off the wall with no warning," Canadian climber Peter Zabrok, 57, told the AP. He said he was scaling El Capitan above the site of the rock fall when the incident happened.
Officials did not identify the person who was killed or the person who was injured. It was not immediately clear whether they were tourists or climbers. Park ranger Scott Gediman told the AP that at least 30 climbers were on the wall when the rock fell.
The injured person was taken to a hospital outside the park for treatment.
The rock fall comes as visitors flock to the park for climbing season, according to the National Parks Service.
The park remained open despite the incident.