LANGLEY, Ark. -- Crews got to work Sunday looking for bodies in the many piles of debris that collected after a flash flood swept through a popular campground, as police drastically cut their search to just three missing campers.

Authorities haven't been able to contact some of the nearly two dozen people who hadn't been accounted for Saturday, but they don't believe those people were in the Albert Pike Recreation Area, the section of the Ouachita National Forest hardest hit by flooding, State Police spokesman Bill Sadler said.

He said those people are likely camping elsewhere in Arkansas, and that's why they haven't been reachable.

"Typically when people go on vacation or camping trips, they want to turn those cell phones off," Sadler said. "That's the reason they're on vacation."

The number of missing has varied wildly since the floods hit partially because authorities have struggled to figure out exactly who was in the campground. Cell phone service is poor in the area, and authorities fielded calls about at least 73 people who couldn't be reached after the pre-dawn Friday flood that killed at least 18 people. A register that would have showed who was staying at the campground was washed away.

Crews have searched most of the 20-mile area down river of the campground, so they focused their search effort Sunday on clearing the many tangled piles of debris that collected along Little Missouri River.

Hopes of finding anyone else alive wilted in the oppressive heat and humidity that blanketed the area all weekend. Temperatures Sunday were expected to reach 97 degrees.

The group of anxious survivors and relatives who took sanctuary at a church in the nearby town of Lodi while waiting for word of missing loved ones had thinned noticeably on Sunday, when the group was to be taken on a tour of the campground.

Suzanne Horsley, spokeswoman with American Red Cross, said about a dozen people from two families were still staying at the church, but that she didn't know what states the families were from.

Graig Cowart, the pastor who has tended to families all weekend, said he would give an informal sermon at the campground and would read a verse from the Book of Romans that conveys the message that everything comes together for God's good. He said the message could help them in the difficult days ahead.

"You want people to escape for a moment and focus on God, but they're going to return to the reality of what they're here for," Cowart said.

The last time someone was found alive was late Friday morning. Only two bodies were found Saturday as swollen rivers subsided and anguished relatives awaiting word of loved ones grew more and more frustrated, knowing that at some point the search mission would become one of recovery.

"They're just devastated. The time for shock has probably gone and now it's just anxiety building. They're beginning to fear the worst," Cowart said.

Five of the 15 victims identified, including three young children, were from a single Louisiana town, Gloster. Three other victims also were from Louisiana, and six were from Texas.

The only Arkansas victim identified was Leslie Jez, a 23-year-old mother and wife from Foreman whose husband, Adam Jez, was listed among the flood's survivors.

"So ready to go camping this weekend," she wrote on her Facebook page Monday. "Kaden is going to love it!!" She later added: "Not looking foward to that cold water, but sounds like I might change my mind after seeing how hot it's supposed to be."

Authorities haven't said whether the child survived.

Floodwaters rose as swiftly as 8 feet per hour, pouring through the remote valley with such force that they peeled asphalt from roads and bark off trees. Cabins dotting the river banks were severely damaged, and mobile homes lay on their sides.

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

About 200 searchers combed some 20 miles of wilderness Saturday searching the thick brush and rivers for survivors and bodies. Experts said many of those killed could be trapped under fallen trees and rocks, and that the water likely won't be clear enough to see through for several days.

The last body found Friday night was retrieved 8 miles downstream from the campground, and authorities Saturday combed the headwaters of Lake Greeson, a large body of water about 20 miles from the camp that would be the furthest any of the bodies could travel.

Tom Collins, a Spring Hill volunteer firefighter, said the debris in the water was frustrating their attempts to recover bodies, and that there were so many fallen trees that it looked like a beaver dam.

"It's just a tangled mess," Collins said.

Authorities have vowed to keep searching until all the missing are accounted for.