A rockfall on the sheer face of Half Dome last weekend destroyed part of a popular climbing route that was first established on the granite monolith in 1957.
“Rockfalls have altered climbing routes before,” said Greg Stock, geologist with Yosemite National Park. “But never one this popular.”
The rockfall did not affect the cable route to the top of Half Dome that is popular with hikers.
The rockfall took a thin sheet of rock measuring roughly 100 feet by 200 feet — about 800 cubic meters — off the sheer face. But Stock suspects that people will want to re-establish the popular climbing route, known as Regular Northwest Face, as soon as possible.
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“People will want to get back up there and climb it,” said Stock, who noted that the route — the first established on Half Dome’s sheer face — will still be open as Yosemite’s climbing rangers investigate changes caused by the fall.
People deciding to make the climb will either have to take an alternate route around the area of collapse or put in new bolts to re-establish the path over the damaged area, according to Jodi Bailey, a Yosemite National Park spokeswoman.
Not everyone in the climbing community is eager to get back on the wall, though. David Allfrey, 30, of Las Vegas, has been rock climbing for the last 10 years. He estimates he has climbed the Regular Northwest Face of Half Dome “at least a half dozen times.” He is apprehensive about doing it again any time soon.
“That entire face of Half Dome is like layers of an onion, and that part that fell off is just a small part of a larger piece,” said Allfrey. “I’m afraid of the rest of it going.”
The reason for the collapse is unknown at this time, but Stock did note heavy rain was falling in Yosemite Valley at the time. He suspected that water from those storms might have been the trigger.
According to Stock, rockfalls happen in the Yosemite Valley all the time, with smaller rockfalls occurring about once a week. Falls of this size happen about once every year. Any rockfall has the potential to be dangerous.
“If anyone was below the rockfall when it happened, they would have died,” said Stock.
Fortunately, the Half Dome fall occurred during a storm in the middle of the night, so no climbers were present. Stock said that so far the event seems to have no witnesses. He estimates that the collapse occurred some time very late on July 2 or in the very early morning of July 3.
In 2014, Yosemite documented 77 rockfalls, the largest of which was on March 31 when roughly 5,000 cubic meters of rock fell from the north wall of Hetch Hetchy valley near Wapama Falls. That rockfall buried a section of the Rancheria Trail, which was closed for weeks until it could be rebuilt.