A major flash flood at the Grand Canyon forced the evacuation of dozens of people and swept large boulders, metal structures and other debris into the Colorado River that runs through it, the National Park Service said.

The flooding in Bright Angel Creek, which flows into the river, happened Saturday afternoon. Torrents of water wiped out footbridges over the creek and significantly altered the landscape, widening the creek bed and creating what appeared to be a new river rapid.