1996 Yosemite Valley landslide occurred on July 10 , 1996 , near the Happy Isles trailhead in Yosemite Valley , Yosemite National Park , Mariposa County , California . 162,000 tons of rocks and other debris fell to the ground at over 160 miles per hour . Of the 12 campers/hikers involved in the incident , one was killed . The landslide competes with the 1997 Merced River flood and the 2013 Rim wildfire for the designation of the worst natural disaster in Yosemite to date
2013 Rim wildfire
Rim Fire
1996 Yosemite Valley landslide