Breaking News Emails

Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

Dozens of searchers are scouring a swampy national park in South Carolina for a father and his two children who disappeared Saturday during a hike, officials said.

Congaree National Park in Richland County, S.C., was closed Monday as search crews combed through thousands of acres of parkland in search of Jerry Robert "J.R." Kimbler, his 10-year-old son and his 6-year-old daughter, said National Parks Service spokeswoman Dana Soehn.

Kimbler, 43, and his young children departed for the hike from the Harry Hampton Visitor Center around 5 p.m. Saturday, according to Soehn.

Soehn said the last known contact with the missing trio was a text message Kimbler sent to a friend at 9:30 p.m. Saturday. Kimbler told the friend that he was lost — and the friend quickly reached out to the mother of Kimbler's kids, who alerted park rangers, according to Soehn.

Search teams have already picked through 9,000 acres of the 27,000-acre park on foot, on boats and on helicopters as the frantic search mission came up on the 48-hour mark Monday with no sign of Kimbler and his kids, Soehn said.

Searchers gather Monday morning at Congaree National Park in Hopkins, S.C.Jody Barr via WISTV

"This has been a very difficult search," Soehn said, adding that search crews faced high water, dense vegetation and obstructions like tree limbs topped by the winter's brutal ice storm.

"The terrain has been very difficult for the searchers. Some areas that would've been a 30-minute walk down the trail are turning into a 2-hour scramble over thickets," Soehn said.

In addition to emergency personnel, the missing children's mother, Tammy Ballard, walked the trails early Monday yelling her kids' names, according to NBC affiliate WIS 10 in Columbia, S.C.

"I can't sleep," Ballard told the station. "I can't do anything. I don't know where my babies are."

Park officials had no idea Monday how the father and his children managed to veer off the park's marked trails.

— Daniel Arkin