At least 16 people have been killed and scores are missing and feared dead after a campsite in the US state of Arkansas was hit by a powerful flash flood.

Waters rose as quickly as two and a half metres an hour as campers slept early on Friday, carrying away tents and overturning massive camper vans.

Heavy rains had caused the normally quiet Caddo and Little Missouri rivers to burst their banks during the night and around dawn, floodwaters surged into the Albert Pike Recreation Area, a campsite in the Ouachita National Forest that was packed with vacationing families.

The raging torrent poured through the valley with such force that it peeled asphalt off roads and bark off trees.

Cabins dotting the river banks were severely damaged and mobile homes lay on their sides.

Scores missing

Two dozen people were hospitalised and 60 others were rescued but relatives reported more than 73 people missing.

Forecasters had warned of the approaching danger during the night, but campers could easily have missed those advisories because the area is isolated.

John Nichols, a forest service spokesman, said it would have been impossible to warn everyone that the flood was coming - the area has spotty mobile phone service and no sirens.

Mike Beebe, the governor, said damage at the campsite was comparable to that caused by a strong tornado; the force of the water carried one body 13km downstream.