A rock climber plunged to his death near the top of El Capitan after a large granite flake broke off the wall and severed his climbing rope, Yosemite National Park officials said Monday.

Mason Robison, 38, of Montana, was 2,300 feet up on the granite cliff known as the Muir Wall when the rock cracked loose, according to Yosemite spokeswoman Kari Cobb. He fell 230 feet and came to a jerking halt at the end of his haul line, a rope he was using to carry gear, as his climbing partner watched in horror.

It wasn't clear whether Robison hit a ledge or struck the rock wall, Cobb said.

"It's a very, very sad situation," Cobb said. "A tragic, tragic accident."

Robison, the lead climber, was about 30 feet above his belay partner and roughly 600 feet below the top of the climb, which is just to the left of the Nose, or prow of El Capitan. The two men had already ascended 26 pitches of a climb that normally takes three to five days to summit.

Robison had just placed a piece of gear that holds the rope known as a cam behind a flat chunk, or flake, of rock and began climbing over the flake. Cobb said he was on top of the flake when it dislodged, severing his rope and taking him down with it.

Robison would have fallen 2,300 feet if he hadn't been trailing a haul line holding his and his partner's food and gear. It was attached to the wall near his partner and apparently stopped Robison in midair, where he hung motionless.

His partner yelled for help, and he and several other climbers called Yosemite search-and-rescue crews, who helicoptered to the top of the mountain. Two rescuers rappelled down from the top. Robison was pronounced dead at the scene. His partner was not injured, Cobb said. They were taken off the mountain via helicopter.

Tourists and others watched the drama from the valley below using binoculars and telescopes.

"I was horrified, to say the least," wrote Tom Evans, who regularly tracks climbers on his blog post ElCap Reports. "In all my 18 years of photographing El Cap, I have never seen such a grisly, terrible scene."

Danger, Cobb said, is unfortunately an integral part of the climbing trade.

"Yosemite obviously is a mecca for climbing," she said. "Every year we do get a number of climbing accidents. Some of them result in fatalities, and some of them result in great bodily injury."