FLAGSTAFF, Arizona: 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 and has left the park service seeking information about 15 people who may be missing or unaccounted for.

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.

As the park service tries to account for everyone in the area, it is asking asked anyone with details about people hiking or camping there to get in touch. It said it was working with the Arizona Department of Public Safety to continue evacuations Sunday.

“This is a reminder of what a dynamic and active landscape Grand Canyon is,” said Jack Schmidt, director of the Center for Colorado River Studies at Utah State University.