Updated

Searchers in airplanes, boat and on foot were looking Monday for a father and his two children who haven't been heard from since sending out a text Saturday that they were lost in the vast woods and swamps of the Congaree National Park east of Columbia.

Crews were carefully marking each patch of land they cross over and have searched about a third of the 27,000-acre site, park spokeswoman Dana Sohen said Monday afternoon.

J.R. Kimbler sent a text message to a friend Saturday around 9:30 p.m. saying he and his kids were lost. The friend called the children's mother, who called authorities. A search party was immediately sent out. A few people at the park have reported hearing someone yelling for help, Kimbler's family said, but Sohen said authorities haven't been able to confirm any contact since the text message.

Officials closed the park Monday afternoon so they could fully concentrate on finding 43-year-old J.R. Kimbler, his 10-year-old son, Dakota, and 6-year-old daughter, Jade. Also, an investigate team from the National Park Service was checking on leads outside the park in case the family members weren't actually lost while hiking, Sohen said.

"We haven't dismissed any possibility," Sohen said.

The mother of the two children, Tammy Ballard, has been at the park the past two days, walking down trails, calling their names.

"It's been tough. I see so many footprints out there," Ballard said.

The search was going to continue until dark Monday and then resume at daylight Tuesday. But after two days of mild, tranquil weather, heavy rain and storms were forecast to move into the area.

Also, there is no indication Kimbler took any camping gear or other items for an overnight stay. The taxi driver left his cigarettes in his cab that was still parked near the visitor's center Monday and his daughter's inhaler and other medicine were in the hotel room where he lived, his family said.

"I hope for the best, but it looks bad every hour that goes by. I'm worried they won't ever come home," said Chris Ballard, stepbrother of the missing children.

Kimbler had been out of his children's lives for a few years, but recently started to get them on the weekends, Chris Ballard said. He took them to the skating rink and the zoo in recent weeks. The trip to Congaree National Park was the first time he had been out there, he said.

The park has marked trails, but beyond the paths are tangles of old growth trees, swamps and underbrush. The land has become even more rugged since an ice storm in February knocked down thousands of trees and limbs.

"Many of the trails you can't see to navigate right now," Sohen said.

Maybee Harris said she has no doubt her cousin is still lost in the woods with his children. She thinks they might have run off the trail to look and something and got lost, then Kimbler's cellphone died.

"They can't convince me he would do something to harm them," she said.