The huge rock chunk that fell Thursday, injuring one person and sending a cloud of dust over Yosemite Valley, was between 400 and 500 feet in length.
Park officials closed one of the exit routes from the park after a massive hunk of granite detached Thursday from the famed rock formation and plunged down, filling Yosemite Valley with dust and injuring a man.
Park spokesman Scott Gediman said the couple were not climbing when a huge sheet of granite sloughed off the iconic monolith. There's no word on his condition.
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 El Capitan's Dawn Wall in 2015.
"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. His wife sustained injuries and is now being treated at a local hospital.
Hayden Jamieson plans to head up the giant El Capitan rock formation on Saturday.
Gediman says the two were hiking at the bottom of El Capitan's vertical face in preparation on their way to scale it when the rock fell.
Rock falls are common in Yosemite but seldom fatal.
Foster's former colleagues at the Up and Under outdoor gear store in Cardiff, Wales, recalled him Friday in a statement as a man whose passion for the outdoors, "and mountains in particular, was enormous and infectious".
The rock falls came during the peak of the climbing season for El Capitan, with climbers from around the world trying their skill against the sheer cliff faces. His wife, Lucy Foster, was injured and is recovering in a Modesto hospital.
Officials had no immediate estimate for how much the big rock weighed but Gediman says all of the rock falls Wednesday weighed 1,300 tons (1,100 metric tons) combined.
The scientists are trying to determine how big the second rock fall was and how it happened.
Two large rockfalls at El Capitan in Yosemite National Park left a man dead and two other people hurt, but this natural phenomenon is not all that uncommon.
The park indicated that seven rock falls actually occurred during a four-hour period Wednesday on the southeast face of El Capitan.
The park says it reports about 80 of them every year.