A six-year-old boy rescued Friday after being buried deep in a sand dune at a national park in Indiana is in critical condition at the University of Chicago Medicine Comer Children's Hospital, according to hospital spokesperson Lorna Wong.
Rescue teams and private excavation crews dug for more than three hours Friday on the northern slopes of Mt. Baldy before rescuing the boy.
Michigan City Fire Chief Ronnie Martin told NBC News the boy was evacuated by helicopter to a hospital in Chicago. The boy’s identity was not immediately released.
“He is listed in critical condition, but when he arrived he was able to respond to simple commands and he has responded well to mechanical ventilation,” Wong said in a statement on Saturday.
"His parents want to extend their deepest thanks to the Michigan City fire and police departments and all the authorities, private companies and individuals who contributed to the rescue effort. They also ask that people include this little boy in their prayers," Wong said.
Many details remained unclear a day after the boy’s rescue. A La Porte County, Ind., coroner's official initially indicated that the hole was more than 30 feet deep, but at a briefing for reporters late Friday, Ranger Bruce Rowe, a spokesman for the National Park Service, said the boy was found under 11 feet of sand in a dune.
The boy's age was initially reported as 8 before the Park Service clarified that he is 6 years old. And Rowe said it was still unknown why he was on a dune in a restoration area of the park away from the public.
Rescue crews were called to Indiana Dunes National Lakeshore, on the Lake Michigan shore in Michigan City, shortly at 4:30 pm local time, Rowe said. The boy was found at 8:05 pm, he said.
The boy's family saw him in the hole as it collapsed and tried to pull him out, Rowe said. They failed and called 911.
Two private excavating companies with heavy equipment joined local police and rescue crews, La Porte County emergency workers, Northern Indiana Public Service Co. workers and National Park Service officers in working to dig out the boy.
"This has not happened before, and we will certainly not let people on the dune until it is safe," Rowe said.
NBC News' Tracy Jarrett contributed to this report.