A powerful flash flood tore through Arizona’s Grand Canyon, sending torrents of muddy water, boulders and debris through Bright Angel Canyon and into the Colorado River. The National Park Service (NPS) said at least 20 people may be missing or unaccounted for, prompting a public appeal for information.

Officials say dozens of people have been evacuated from the depths of the Grand Canyon because of heavy rain and flooding.

More than 60 people had been evacuated from Grand Canyon National Park due to flash flooding, but some people are unaccounted for.