Forty to 50 adults and children were stranded Saturday along various sections of Bear Canyon northeast of Tucson as the waters rushed down mountainsides, the Pima County Sheriff's Department said.
A series of 911 calls from hikers sparked a rescue operation involving teams on the ground and in a helicopter,
The first group of hikers was led out of the canyon in the Catalina Mountains in the late afternoon and the last group well after dark, deputy Tom Peine told the Arizona Daily Star.
Some of the hikers said they were stranded when a river swelled to a raging torrent in a matter of minutes.
"I've never seen anything like this," hiker Jesse Boyd told KGUN-TV. "I've gotten caught in rain out here, but nothing to the point where I had to be rescued."
With some hikers, rescuers used a technique that involved roping them together with flotation devices to help get them through high water. Some of the hikers were flown out by helicopter.
"(A) rescue team member was behind us with a hand on that flotation device," Michael Rolland told KVOA-TV after being aided by rescuers. "They strung a rope across, and so we had to grab the rope and sidestep across the river."
Peine said that the hikers might not have realized that rains at higher elevations could cause canyon flooding long after the down pour ends.