Caddo Gap - Flash floods swamped valley campgrounds along a pair of southwestern Arkansas rivers early Friday, killing 16 and leaving anguished families pleading with emergency workers for help in finding dozens of missing people.

More than 40 people were unaccounted for after the Caddo and Little Missouri rivers rose quickly overnight - at times faster than 8 feet per hour, said Gary Fox, a retired emergency medical technician who was coordinating with families to determine who had died and who had yet to be found.

"This is not a one- or two-day thing," Fox said outside a command post near Langley next to the Little Missouri. "This is going to be a week or two- or three-week recovery."

The Albert Pike Recreation Area, a 54-unit campground in the Ouachita National Forest, was packed with vacationing families, many of them from Louisiana and Texas, Fox said. Two dozen people were hospitalized and another 60 were rescued from the steep Ouachita Mountains valley.

"It's a lot of tragedy. I cannot even imagine what the families are going through," Fox said.

It was unlikely that many of the missing could have left the area on their own after the flood. Fox said nearly everyone lost their vehicles when the floodwaters swept through the recreation area.

The heavily wooded region hosts a mix of campgrounds, hunting grounds and private homes. Wilderness buffs can stay at sites with modern facilities or hike and camp off the beaten path.

Cabins dotting the banks of the river were severely damaged. Boards hung lopsided from rooftops, and porches were missing rails. Some trees were flattened by the water, bent to the ground by the force of the flood. Others had bare spots where the water apparently wiped the bark clean from their trunks. Mobile homes lay on their sides.

Brigette Williams, spokeswoman for the American Red Cross in Little Rock, estimated that up to 300 people were in the area when the floods stormed through.

"There's no way to know who was in there last night," state police spokesman Bill Sadler said. It would be difficult to signal for help because of the rugged and remote nature of the area being searched, some 75 miles west of Little Rock.

"This is not an area you would typically be able to get a cell signal out of," Sadler said.

The Arkansas Department of Emergency Management sent satellite phones and specialized radio equipment to help in the rescue effort.

The rugged terrain likely kept some campers from reaching safety, according to Tabitha Clarke, a hydrologist with the National Weather Service office in North Little Rock. Some parts of the valley are so steep and craggy that the only way out is to hike downstream. Any who had taken cars to the camp sites would have been blocked at low-water bridge crossings that are inundated when the rivers rise, she said.

Many campers were likely still asleep when their tents began to fill with water, she said.

Marc and Stacy McNeil of Marshall, Texas, survived the flooding by pulling their pickup truck between two trees and standing in the bed in waist-deep water.

"It was just like a boat tied to a tree," Marc McNeil said, describing how the truck bobbed up and down.

They were part of a group of seven on their first night of camping in tents. The rain kept falling and the water kept rising throughout the night, at one point topping the tool box in the back of the truck.

"We huddled together, and prayed like we'd never prayed before." Stacy McNeil said.

By dawn the rain stopped, the water receded and they were able to walk to safety.

Searchers worked along the Little Missouri River in Montgomery and Pike counties, while along the Caddo River at Glenwood police and fire crews monitored debris moving beneath the U.S. 70 bridge.

The National Guard dispatched helicopters to help in the rescue because much of the area was inaccessible by land. Tracy Farley of the U.S. Forest Service said the floods eroded some road beds and knocked trees across roads. Crews with bulldozers and chain saws were sent to the area.

Helicopters landed behind a general store in the town of Langley. Nearby a command post had been set up outside the post office and a triage unit was set up at a volunteer fire department.

Meliea Moore of Hot Springs waited at the general store with her friend whose sister, brother-in-law and niece were missing. They had been staying in a cabin for the past week at the campground.

A center for relatives of the missing was set up at a church in Lodi where dry clothes and food were available. Williams said the Red Cross would provide shelter for anyone displaced by the flooding.

Sadler said bodies were being moved to funeral homes in Mena. He did not have any information on the ages or identities of the dead.

Health Department officials arranged for transportation of the dead and said they would help with identification.

Arkansas Gov. Mike Beebe's spokesman, Matt DeCample, said Beebe was heading to Montgomery County on Friday.

Clarke, of the National Weather Service, said the water rose quickly between 1:30 a.m. and 5:30 a.m. A river gauge at Langley, just south of the Camp Albert Pike area, had a peak reading of 23.39 feet - up from 3 feet deep at midnight.

A flash flood warning was posted for the area at 1:57 a.m. after a slow-moving storm dumped heavy rain. At that point, the Langley river gauge showed the Little Missouri was still below 4 feet.

Between 2:45 a.m. and 3:45 a.m., the river rose 8.08 feet and continued to rise, according to data from the U.S. Geological Survey, which monitors the gauge.

Weather service readings showed that 7.6 inches of rain fell in the area overnight.

Raw Video: Aftermath of Ark. Floods That Kill 16