Four bodies have been recovered after a popular swimming hole in Arizona was suddenly engulfed by flash flooding, with a child among the dead.

Local fire chief, Ron Sattlemaier, told the Associated Press that over a hundred people were enjoying the Cold Springs swimming hole in Tonto National Forest around central Arizona when the tragedy struck on Saturday (15 July).

"They had no warning. They heard a roar and it was on top of them," Sattlemaier said.

A thunderstorm upstream rushed down from an area recently cleared by wildfires and in no time had flooded the area families were spending the afternoon, authorities said.

"I wish there was a way from keeping people from getting in there during monsoon season. It happens every year," said Sattlemaier

At least a dozen people are still missing, while four were rescued and taken to hospital by helicopter for hypothermia treatment. Three of the bodies were found on Saturday while the fourth was recovered on Sunday.

Sattlemaier added that they could not know how many people had actually been at the swimming hole at the time of the incident but that now it was "pretty much recovery".

"We don't believe there's anybody left out there." Sattlemaier said.

Tonto National Forest is one of the largest national forests in the United States, covering almost three million acres.

Tonto National Forest
A hiker in an area of Tonto National Forest, ArizonaREUTERS/Deanna Dent