The group from the Phoenix and Flagstaff areas had met Saturday for a day trip along a popular swimming hole near Payson, about 100 miles northeast of the capital. They set up lounge chairs not knowing an intense thunderstorm was dumping heavy rainfall just upstream in the Tonto National Forest.
The storm unleashed 6-foot-high floodwaters, dark with ash from a summer wildfire, onto the unsuspecting family and friends. The torrent carried away tree branches and other debris and left a wake of nine bodies.
Search and rescue crews, including 40 people on foot and others in a helicopter, recovered the bodies of five children and four adults, some as far as 2 miles down the river. Authorities did not identify them.
A 13-year-old boy from the same group was still missing Sunday.
Disa Alexander was hiking to the swimming area where Ellison Creek and East Verde River converge when the water suddenly surged.
Video she posted to social media showed torrents of water surging through jagged canyons carved in Arizona's signature red rock.
"I could have just died!" Alexander exclaimed on the video.
She spotted a man holding a baby and clinging to a tree. Nearby, his wife was also in a tree. A boy Alexander described as the couple's son was on the rocks above the water.
Had they been swept downstream, they would have been sent over a 20-foot waterfall, Alexander said.
Alexander and others tried to reach them but couldn't.
Fortunately help was close by.
Some search and rescue team members were already near the swimming hole after getting a call to help someone who had suffered a bad allergic reaction, according to Detective Sgt. David Hornung of the Gila County Sheriff's Department.
When they arrived at the scene, "they heard someone screaming for help and saw a man clinging to a rock," said Hornung, who added that the man was safely rescued. "Then they heard other people calling for help."
Four people were rescued and taken to the hospital for treatment of hypothermia.
Some 40 rescuers in bright orange T-shirts and helmets dotted the green landscape as they combed the waters and banks for the missing boy. A few brought along specially trained search dogs hoping to find him alive, Hornung said.
The family, who was staying in the area, declined to be interviewed when approached by an Associated Press reporter.
The National Weather Service estimated up to 1.5 inches of rain fell over the area in an hour. The thunderstorm hit about 8 miles upstream along Ellison Creek, which quickly flooded the narrow canyon where the swimmers were.
Hornung noted that the National Weather Service had issued a flash flood warning about 1 1/2 hours before, "but unless they had a weather radio out there, they wouldn't have known about it. There is no cell phone service out here."
The swift waters gushed for about 10 minutes before receding in the narrow canyon, Hornung said.
"They had no warning. They heard a roar, and it was on top of them," Water Wheel Fire and Medical District Fire Chief Ron Sattelmaier said.
While Arizona is known for its dryness, it gets bursts of heavy rains during the summer monsoon season. The severe thunderstorm was located in a remote area that had been burned by a recent wildfire, Sattelmaier said. The "burn scar" was one of the reasons the weather service issued the flash-flood warning.
"If it's an intense burn, it creates a glaze on the surface that just repels water," said Darren McCollum, a meteorologist
Crowds looking to beat the Phoenix metro area's heat often head to the small creeks that flow out of the mountains forming swimming holes and a series of small waterfalls. But officials warn that visitors need to be aware of the dangers of a flash flood.
"I wish there was a way from keeping people from getting in there during monsoon season, " Sattelmaier said "It happens every year. We've just been lucky something like this hasn't been this tragic."
Steve Stevens, a volunteer fire fighter with Water Wheel Search and Rescue, said visitors should stay away when there are flash flood warnings.
"The clouds over on the other side of the mountain can be dumping buckets, and all of a sudden there's a wall of water coming through that just wipes out everything in its path," said Stevens, who has lived in the area for 20 years.
Sudden flooding in canyons has been deadly before. In 2015, seven people were killed in Utah's Zion National Park when they were trapped during a flash flood while hiking in a popular canyon that was as narrow as a window in some spots and several hundred feet deep.
In 1997, 11 hikers were killed near Page, Arizona, after a wall of water from a rainstorm miles upstream tore through a narrow, twisting series of corkscrew-curved walls on Navajo land known as Lower Antelope Canyon.
The Associated Press contributed to this report. Ho reported from Las Vegas. Alina Hartounian in Phoenix and Mike Balsamo in Los Angeles contributed. Angie Wang also contributed to this report from Tonto National Forest.
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