"The release point appears to be near the "Waterfall Route", a popular climbing route on the East Buttress of El Capitan".
Gediman says the injured person was being taken to a hospital near the park.
Climber Kevin Jorgeson said he and climbing partner Tommy Caldwell 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.
In 2013, a rock dislodged and severed the rope of a Montana climber who was scaling El Capitan. At least 30 climbers were on the wall at the time, but it was not clear if the victims were climbers or tourists, ranger Scott Gediman said.
The rocks peel off in giant slabs because they are destabilized by small contractions that come with changes in season and temperature. The male victim was found dead and the female was flown out of the park with serious injuries.
"We saw a huge plume of smoke from the summit of Half Dome and later found out it was a fatal rockfall", he told CNN.More news: Brawls in Uganda parliament for second day over presidential age limit
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Officials did not identify the person who was killed or the person who was injured. "Once we saw how quickly it dissipated, we knew it wasn't a fire".
El Capitan is considered the "Mount Everest of rock climbing", with thousands ascending it each year.
Images showed a woman being carried into a helicopter by two rescue workers.
Yosemite remained open and visitor services were not affected, Gediman said.
Longtime Yosemite climber Peter Zabrok (ZAY'-brok) says he's never seen anything like the chunk of rock that broke off. Zabrok said it was as big as an apartment building.