YOSEMITE, Calif., March 29 (UPI) -- A number of factors can encourage rockfalls, and not all of them are easily monitored. Temperature, however, is easily measured, and new research suggests heat triggers rockfalls along the steep granite walls of California's Yosemite National Park.
For the last three years, researchers with the National Park Service and U.S. Geological Survey have been monitoring the links between weather and rockfalls in Yosemite. Their data suggest rockfalls are more likely during the hottest time of the day during the hottest portion of the year.