Arizona law enforcement officers have rescued a dozen hikers trapped in raging floodwaters but two remain stranded overnight in a wilderness area just east of Tuscon, officials said.

Dramatic video footage showed a Pima County Sheriff’s Department helicopter hovering over the rock-covered, fast-moving water of the Tanque Verde Falls as a rescuer was lowered on a line to save two hikers. The sheriff’s department, together with the Southern Arizona Rescue Association and Rural Metro Fire Department pulled at least a dozen from the water as of late Sunday, including a 4-year-old boy, authorities said.

The rescue happened in a spot known as Redington Pass, a high mountain area of Tanque Verde Canyon, about 20 miles east of Tuscon.

As of late Sunday, two men remain trapped on a ledge on the far side of the canyon, according to the rescue association. Conditions were unsafe for the helicopter to retrieve them. A team of rescue association volunteers on foot made contact from the near shore and was waiting the night to keep an eye on them. Another team was hiking to access the men from the far side with the intention of descending the cliff to reach them.

“At that time water levels will be reassessed and a decision will be made to help them out on the far side or cross the stream if conditions are safe,” according to the rescue association.

Law enforcement officials said that area is known for flash flooding.

“It takes time for the water to flow from the mountain down to the valley, and when it does it can be swift and deadly,” according to the sheriff’s department. “All too often, hikers decide to hike just after it rains because the air temperature is cooler, not realizing they are walking into areas which are at an increased risk for flash flooding.”

ABC News’ Kate Hodgson and Matthew Fuhrman contributed to this report.