As rescuers searched Monday for a 27-year-old man still missing about 100 miles (160 kilometers) northeast of Phoenix, authorities identified the victims, who ranged in age from 2 to 60.
Among them were three generations of a family. Five of the dead were children.
The victims had been lounging Saturday in the swimming hole, where rocks create pools and a series of small waterfalls. There the river narrows, squeezing the flow of water and increasing its deadly force.
The river roared to life after a thunderstorm had dumped up to 1.5 inches (3.8 centimeters) of rain in an hour, prompting a flash-flood warning from the National Weather Service.
Though the service sent out a flash-flood warning over cellphone networks, service in the remote area is patchy at best. Unless they had a weather radio, the swimmers would have been unaware.
"They had no warning. They heard a roar, and it was on top of them," said Fire Chief Ron Sattelmaier of the Water Wheel Fire and Medical District.
Carrie Templin, a spokesman for the Tonto National Forest, said people headed to the forest should check weather alerts ahead of time to determine whether it's safe. It is hard to predict where rain will fall in the desert Southwest, and people should know that heavy downpours can cause flash flooding, Templin said.
One hiker who was stranded by the flood said she can't get the sound of the rushing water out of her head.
Nancy Coto, 17, said she was stuck for four hours on a slab of rock with her boyfriend and his family before they were able to walk out.
"We're all just saying that we got blessed, but I don't like to use that word because other families weren't blessed," Coto said. "Children died."
About 40 volunteer workers and four search dogs looked for the missing man, whom authorities identified as Hector Garnica.
Garnica had come to celebrate his wife's birthday with their three children and other family. All were among those killed.
Authorities and a family member identified the dead as 2-year-old Erica Raya-Garcia; Emily Garnica, 3; Mia Garnica, 5; Danial Garnica, 7; and Jonathan Leon, 13. Also killed were Javier Raya-Garcia, 19; Celia Garcia Castaneda, 60; Maribel Raya-Garcia, 24; and 26-year-old Maria Raya-Garcia, Hector Garnica's wife.
The group went up the mountain early Saturday, said Tom Price, the general manager at The Horny Toad, a restaurant where Hector Garnica worked.
Garnica's parents were eating at the restaurant in a Phoenix suburb Saturday night when they got a call that something had happened, Price said.