On the afternoons of September 27 and 28, a series of rockfalls occurred on the far right side of El Capitan, near the line of Horsetail Fall. The initial rockfall on September 27 struck two climbers who were walking along the base of the cliff after retreating from the East Buttress route. One of the climbers, Andrew Foster, 32, from Wales, was killed by the rockfall. Witnesses reported that he had rushed to shield his wife from the debris when he was hit. She was seriously injured and was transported by short-haul helicopter rescue to El Cap Meadow and then to an area hospital for treatment.

Over four hours, six more rockfalls occurred, for a total volume of about 450 cubic meters (a cubic meter is about the size of a washing machine) or about 1,340 tons.

A much larger rockfall occurred in the same general area on September 28. This one measured 10,250 cubic meters in volume, or about 30,500 tons. The rockfall generally propagated upward and outward from the origin of the September 27 rockfall, greatly expanding the overall source area. Boulders reached the Valley floor, and smaller fragments traveled to Northside Drive. One piece struck a vehicle, hitting the driver and causing a head injury.

The September 28 rockfall ranks as the 29th largest on record in Yosemite. It had been 18 years since the last rockfall-related fatality in the park, when climber Peter Terbush was killed by a rockfall from Glacier Point on June 13, 1999.

ANALYSIS

Most rockfalls in Yosemite occur in the winter and early spring, during periods of intense rainfall, snowmelt, and/or subfreezing temperatures, but large rockfalls—like these ones from El Capitan—have occurred during periods of warm, stable weather.

How can climbers address rockfall risk? Unfortunately there are no hard or fast rules, but rockfall areas are often active for many hours, days, or even months, so avoid climbing in recent rockfall zones. The “progressive” nature of the El Cap rockfalls, with several events from the same location, has also been seen at other locations in Yosemite, including Middle Brother and the Rhombus Wall. Fresh talus and/or damaged vegetation at the base of your intended climb are good indicators of recent activity. Be especially aware of cracking or popping sounds emanating from the cliffs, as these sounds have preceded many rockfalls.

A helmet may not save you from a large rockfall, but it could offer protection from “flyrock” that accompanies most rockfalls. Minimize your time approaching or bivying at the bases of cliffs, particularly those in known rockfall zones. (Source: ClimbingYosemite.com/Yosemite National Park Climbing Rangers.)