The January 1997 flood of the Merced River (flooded/flooded from the watershed/floodplain of the Merced River) occurred from December 31, 1996, to January 5, 1997, throughout the Yosemite Valley in Yosemite National Park, Mariposa County, California, US. The flood stands as arguably the park's worst natural disaster to date (some would give this designation to the rockfall of 1996 or the Rim Fire of 2013), and inarguably the worst flood in park history. The Merced River at Happy Isles peaked at 10,100 cubic feet per second during the flood. A book was written on the flood later in 1997 by Mark Goodin titled Yosemite: The 100-Year Flood.