Heavy rain triggered a major flash flood around Phantom Ranch and Bright Angel Canyon in Grand Canyon National Park on 29 August, sending water and debris into the Colorado River.
Footbridges across Bright Angel Creek were destroyed, while large rocks, mud and damaged structures were swept downstream.
Visitors to the areas were evacuated by helicopters, with 62 people taken from Phantom Ranch and the lower North Kaibab Trail the following morning.
The National Park Service is also seeking information about more than 20 people who may be missing or unaccounted for.
Phantom Ranch, Bright Angel Campground and the North Kaibab Trail remain closed as rescue and assessment work continues.