Flash flooding at Grand Canyon National Park has resulted in over 20 individuals missing, according to park officials. The deluge struck Sunday, sweeping through campgrounds and hiking trails in the inner loop of the Bright Angel Creek corridor.

Authorities are concerned that hikers and backpackers were swept away by the powerful floodwaters. A statement from the Grand Canyon National Park Service on Sunday afternoon revealed that more than 20 individuals “may be missing or unaccounted for” following Saturday’s flash flood.

The National Park Service is urging the public to provide information about anyone who was in the inner canyon along the Bright Angel Creek corridor on August 29, or who had a campground reservation in the affected area. Details on how to report can be found through the National Park Service Investigative Services Branch (ISB).

Park officials confirmed that at least 62 people have been evacuated from the park after the flooding caused significant damage Saturday afternoon. Evacuees were transported to the Maswik Lodge food court on the South Rim, where American Red Cross personnel are providing assistance. No injuries have been reported.

The Park Service also stated that nearly all footbridges spanning Bright Angel Creek were destroyed, eliminating pedestrian access across the creek. Officials warned of additional thunderstorms and heavy rainfall expected Sunday and Monday, which could lead to further flash flooding, debris flows, rockfall, and changes in trail and river conditions.