The identity of a person killed in California's Yosemite National Park remained unknown early Thursday after a granite slab described as "the size of an apartment building" fell off the face of El Capitan the day before.

Rangers from the National Park Service took the injured person to a hospital. It was unclear if any of the approximately 30 climbers on the rock, or park tourists below, was injured, the Los Angeles Times reported.

Photos on social media showed dust billowing skyward from the site of the disaster. Ranger Scott Gediman said Wednesday that the tragic accident was "witnessed by a lot of people."

El Capitan is one of the world's largest granite monoliths, towering 4,000 feet (1,219 meters) above Yosemite Valley.

Several people made emergency calls, reporting the rock fall.

"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," said Canadian climber Peter Zabrok, 57, who was scaling El Capitan and was above the rock fall.

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.

Rock falls are common in Yosemite but seldom fatal.

Ken Yager, a Yosemite climber and historian, said he’s never seen a rockfall-related death at the site.

“It’s pretty rare,” he told the Fresno Bee. “As many rockfalls that go on around here, it’s kind of amazing. It’s kind of a freak accident in some ways.”

Kevin Jorgeson said he and climbing partner Tommy Caldwell once witnessed a massive rock fall in the same area while they prepared for a trek that made them the first people to free-climb the Dawn Wall on El Capitan in 2015.

First they heard a rumble and then they saw a white cloud of dust.

"Yosemite is just a really active, wild place. It's always changing," Jorgeson said. "It doesn't make it any less tragic when someone gets in the way of that."

In 2013, a rock dislodged and severed the rope of a Montana climber who was scaling El Capitan.

Mason Robison, 38, fell about 230 feet to his death. It was Robison's gear digging into the side of the mountain that caused the rock to dislodge.

Yosemite remained open after Wednesday's rock fall, and other activities throughout the park weren't affected, rangers said.

The rock fall happened near the Waterfall route on El Capitan's eastern buttress shortly before 2 p.m. PDT, according to a statement by the National Park Service.

The Associated Press contributed to this report.