(LOS ANGELES) -- Two people are dead and at least one person remains missing following a major flash-flooding event at the Grand Canyon over the weekend, as cadaver dogs are expected to be used in the ongoing search of the devastated areas, authorities said.

The current missing-person count is based on overnight camping permits issued by the park, officials said, while acknowledging that additional day hikers who did not have permits could also be missing.

"There are day hikers that come in the canyon that we don’t know about," Dave Black, the Grand Canyon National Park Service's incident commander, said at a news conference Monday evening.

Black said that the weather is expected to be clear Tuesday for the first time since Saturday afternoon's flash flood, allowing ground crews to be sent to the hard-hit areas. Four teams with cadaver dogs are planning to search the Bright Angel Creek and Phantom Ranch areas Tuesday, he added.

Authorities said hundreds of tips have been received but so far, there is no reason to believe anyone else is missing other than the one person already being sought.

A Border Patrol technical search team will search for the remaining confirmed missing person, Black said. Authorities said they will also use Bluetooth technology and a drone to search the area.

"We are absolutely holding out hope that that person is still alive," Black said.

The National Park Service confirmed that two people have been killed in the deadly flash flooding.

On Sunday evening, officials said the body of a 46-year-old man, whose name has not been released, was recovered near Crystal Rapids along the Colorado River. The family of the other recovered victim identified him as Dr. John Giusti, a Texas chiropractor and married father of three daughters.

Flash flooding unfolded about 2:30 p.m. local time Saturday in the Bright Angel Canyon and Phantom Ranch area, both popular destinations for hikers. Authorities said 82 people were rescued from the canyon, most by helicopter. A couple of people were able to hike out, they said.

Meanwhile, new details have emerged about the response to the flash flood emergency.

Deputy Superintendent Brian Drapeaux of the Grand Canyon National Park Service said at Monday's news conference that water-level gauges installed in Bright Angel Creek following last year's Dragon Bravo Fire on the North Rim of the Grand Canyon stopped working during the flood.

"That system started to alert us of rising waters, and then shortly after, that system went offline as water progressed down the creek and picked up speed and destructive force," Drapeaux said.

It's unclear why the water-level gauge system stopped working, Drapeaux said, adding that debris that filled the creek could have knocked it offline.

Flood survivors told ABC News that they ran for their lives when a flood swept through the floor of the Grand Canyon on Saturday afternoon, wiping out campgrounds, structures, hiking trails and vital infrastructure, according to officials.

"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)," the National Park Service said in a statement.

On Sunday, NPS officials said more than 20 people had initially been reported missing and that 62 individuals were air evacuated from Grand Canyon's Phantom Ranch and the lower North Kaibab Trail, "which was affected by a significant flash-flood event Saturday afternoon."

"The flash flood resulted in significant impacts to infrastructure throughout Bright Angel Canyon. Nearly all footbridges spanning Bright Angel Creek were destroyed, eliminating hiker access across the creek," the Grand Canyon NPS said.

Saturday's flash-flood event occurred after four rounds of rain swept across parts of the Grand Canyon over a span of about six hours, according to the National Weather Service. The initial three rounds were not very heavy but saturated the soil and left the area much more prone to dangerous flash flooding once the fourth round of torrential rain moved through.

The steepness of the canyon and the burn scar from last year's Dragon Bravo Fire on the North Rim were likely major contributors, the NWS said.

Videos of the flooding obtained by ABC News show a roaring Colorado River as mudflows and debris from metal structures are seen floating down the river.

Copyright © 2026, ABC Audio. All rights reserved.