(CNN) -- Arkansas Gov. Mike Beebe, appearing Friday night on CNN's "Campbell Brown," said portable cell phone towers are being placed in areas affected by deadly flash floods to help locate missing campers.
Beebe told CNN's Candy Crowley, who was filling in as the show's host, that the flooding happened in "a remote area away from civilization."
Rescuers were searching into the evening, trying to locate those missing after floods rushed through a popular U.S. Forest Service camping area.
Still, "there is no absolute way of knowing" how many are missing, said Beebe. "There are people who know that their loved ones were in that area camping and so it will be a matter of hours and maybe days and hopefully not much longer than that."
At least 16 people were killed after the little Missouri River rose more than 20 feet in a matter of hours. Beebe said the timing could not have been worse, because "all those vacationers that were camping along the river were asleep."
The federal government has committed considerable resources to the state's search and rescue efforts, he said.
"We have virtually every asset you can have," he said. "This was a national area, a national forest area. So the federal folks are on the scene, but we also have all our state assets as well. We have state agencies, National Guard and the state police."