Nine extended family members from Phoenix died and another one is missing after being swept away in flash flooding in central Arizona, authorities said Sunday.
The thunderstorm hit about 8 miles upstream along Ellison Creek, which quickly flooded the narrow canyon where the swimmers were enjoying a cool dip a on a hot summer day.
A 13-year-old boy from the same group was still missing on Sunday. The victims range in ages between 2 and 60, he said.
At least four people have been rescued from the water and treated for hypothermia.
The National Weather Service in Phoenix said that most of Arizona was under flash flood watch until Monday evening, warning that "heavy rains can produce flash flooding of low lying, normally dry areas such as washes".
"They had no warning", Sattelmaier told the Associated Press.
A teen who witnessed the flash flood spoke with 12 News about what she saw. It is about 20 feet wide and 20 feet long with a waterfall above it.
"It was kind of frightening to have that feeling in the back of your head, there could be people out here needing to be saved and not much you can do about it", Alexander said. Monsoon storms are expected into the middle of the week. It happens every year.
"It wasn't even raining where these people were at", he said.
"If it's an intense burn, it creates a glaze on the surface that just repels water", said Darren McCollum, a meteorologist. He said visitors are reminded to be vigilant about the weather.
Elsewhere in the United States, officials are concerned flooding could impact the start of classes next month. There are past instances like the one in 2015 in Utah's Zion National Park where the toll was seven.
Coto said she's sending prayers to all the family and friends of the victims.