Officials at Grand Canyon National Park say one visitor died and at least fifteen others remain missing or unaccounted for, after a major flash flood raged through parts of the canyon over the weekend.

The flooding prompted evacuations, and damage to critical infrastructure is being assessed as lodging within the park was temporarily shut down on Sunday.

“Grand Canyon National Park will implement Stage 4 water restrictions on the South Rim beginning at noon on August 31 in response to the significant flash flooding that occurred along Bright Angel Canyon on August 29,” park officials said in a statement.

Significant damage was reported along the Transcanyon Waterline, a major source of water to facilities within the park. “The waterline is currently not operational, leaving the park with limited water reserves and requiring significant water conservation measures to ensure available supplies can be maintained,” officials said on Sunday.

The sudden flooding occurred near Bright Angel Creek beginning on Saturday, following an intense period of localized rainfall.

More than five dozen visitors were reportedly evacuated by helicopter from the inner canyon, according to the Associated Press. Arizona Department of Public Safety assisted with evacuations, and officials are still assessing damage to infrastructure as the search for several unaccounted visitors remains underway.

National Park Service officials confirmed that the body of a 46-year-old man was recovered Sunday night near Crystal Rapids, and as searches continue, officials have requested that the public please assist in providing any information about their possible whereabouts.

“The National Park Service is asking anyone who knows of hikers or backpackers who were in the inner canyon along the Bright Angel Creek corridor on August 29, as well as anyone who had a campground reservation in the affected corridor, to provide information to the National Park Service Investigative Services Branch (ISB),” National Park Service officials said in a statement released by Grand Canyon Office of Communications on Sunday.

“This includes individuals who may have been traveling along the North Kaibab Trail from the North Kaibab Trailhead to Phantom Ranch, staying at Bright Angel Campground, or traveling or staying in the area known as ‘the Box’ north of Phantom Ranch.”

Officials also said the floods had been severe enough to wash out several footbridges and even dislocate some large boulders in portions of the Colorado River, altering sections of the river channel, and potentially making some of them unsafe.

Stage 4 water restrictions will remain in effect on the park’s South Rim, and year-round residents have been asked to use water sparingly while repairs remain underway.

Beginning in 2023, efforts began to modernize the park’s water system, culminating in a $208 million rehabilitation project that would provide water for the roughly 1,600 residents of Grand Canyon Village and the millions of annual visitors who enjoy the park.

Damage assessments continue, and National Park Service officials have warned that additional summer storm activity could affect the region.

“Additional thunderstorms and heavy rainfall are possible today and Monday, which could result in additional flash flooding, debris flows, rockfall and changing trail and river conditions,” officials said.

Anyone with information about individuals who remain unaccounted for in Grand Canyon National Park has been asked to contact the National Park Service Investigative Services Branch Tip Line at 888-653-0009.

Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.