The heaviest rains started at 2AM and the Little Misslouri River crested at 5AM with the Caddo River cresting at 8 AM.
The rapid 'runoff' is what created a torrent with huge amounts of torque.
Mountainous terrain doesn't contain a lot of soil or 'absorption' resources. A valley in a narrow canyon can be a dangerous place.
According to Google Maps the surrounding terrain is higher and in many instances, north of the camp, 'far higher' than the valley where the camp resides. Elevation and unexpected weather are the reasons for this disaster.
Trying to gather information on the missing persons, the state set up a call center that will be open until 7 p.m. on Sunday. Any helpful information about the victims of the Arkansas floods can be submitted using the 888-683-2336 phone number
...The authorities say that not all these people are necessarily missing, because some of them might be in a safe location, but unreachable by phone. After the floods hit the federal ground some of the documents containing the names of the campers were destroyed by the water, so that the authorities don’t have a detailed list of everyone who was there at the time of the disaster.
by Frank James
The death toll from the flash flood tragedy in southwestern Arkansas has grown to at least 20 people with dozens of people missing....
http://www.npr.org/blogs/thetwo-way/2010/06/11/127775861/arkansas-flood-update-at-least-16-dead
Air and water are fluid. The movement is the same in many instances, but, the viscosity and 'location' are different. There was probably a whirlpool. Some of the pictures look similar to areas of Katrina where whirlpools removed homes from their foundations.
...Beebe compared damage at the campground to a strong tornado. He says asphalt was ripped from the ground and a tractor-trailer was wrapped around a tree....
http://www.katv.com/news/stories/0610/745063.html
...The upper stretches of the river above Lake Greeson descend 1,035 feet in 29 miles (315 m in 47 km) for an average drop of 35 feet per mile (6.6 m/km). This makes the upper waters of the river excellent for experienced canoers. There is a 4.4-mile (7.1 km) long segment that has been designated as a wild river. This segment contains the Winding Stair Rapid which is classified as a Class IV rapid on the International Scale of River Difficulty. Another attraction on the upper river is Little Missouri Falls, a stair-step fall that attracts photographers and visitors. The upper reaches of the Little Missouri were considered so scenic that the area was once approved by Congress to become Ouachita National Park, until this action was vetoed by President Herbert Hoover. The watershed of the Little Missouri is quite small, which means that its upper reaches ordinarily contain little water during the dry summer months....
http://en.wikipedia.org/wiki/Little_Missouri_River_(Arkansas)
The 'end' of the water's path may prove to be where some people can be found, keeping in mind, the water levels have receded all along that path.
Hopefully, people will still be alive, but, perhaps injured, scared or in shock. I would check tree tops and any caves along the path of the FLOODING.
Eventually some bodies may be entombed in mud and debris.
