California, Yosemite National Park. On 21 March Marcus Cohen, Bob Snively, Elaine Leachman, and Margo Percival (18) were descending the Monday Morning slabs. The accident occurred at the bottom of the second and last rappel. Margo Percival had gone down first on belay and had untied and the belay rope was being hauled up for the next person when a fist-sized rock was dislodged from the belay ledge by the rope and bounced 140 feet down the 60 degree slope and struck her on the forehead at the hairline, above her left eye. Ample warning was given and evasive action was taken, but the rock took a bad bounce in the last 15 feet. The ledge which she was on was well protected and the only further danger was that she might wander along to an exposed place, 30 feet away. She did not lose consciousness and bleeding stopped fairly quickly. She was dazed, but was able to walk the 1/2 mile to the road with assistance. From there a car was flagged and the girl sent to the hospital.
Source: Marcus Cohen.
Analysis: (Cohen) A hard hat could have prevented much of the injury. Two members of the party were wearing them and in retrospect it appears that in groups where there are individuals without them, the first person down a climb or rappel should have one to keep a rockfall hit from producing further injury (such as dazedly walking off the ledge).