Several large rock falls occurred from near the East Buttress of El Capitan on Oct. 11. The first rock fall occurred around 11:30 a.m., and was followed about three minutes later by a much larger rock fall. A third, smaller fall occurred at around 1 p.m. Geologists are still investigating these events and are mapping the size of the failures in detail, but preliminary estimates suggest the volume exceeded 1,000 cubic meters, making this the largest rock fall thus far in 2010.
All three rock falls detached about halfway up the far eastern side of the southeast face of El Capitan, roughly along the path that Horsetail Falls takes when flowing. Rock debris hit a prominent ledge beneath the cliff and fragmented into smaller boulders, producing substantial dust; the dust cloud produced by the second impact was visible throughout Yosemite Valley. Boulders did reach the base of the cliff, but did not impact any trails or roads.
Although there were many climbers on El Capitan at the time, there do not appear to have been any injuries associated with these rock falls. However, climbers are cautioned that future rock falls from this area are possible.
Visit the Yosemite NPS website for more information. –NPS press release