Crews have spotted a second hole at Mount Baldy in Indiana Dunes, just 100 yards east of where six-year-old Nathan Woessner was trapped under 11 feet of sand last month. 

The Environmental Protection Agency and the National Park Service have been out investigating the area since Monday, using radar and ground-sensing equipment to find out what could be causing these holes. Bruce Rowe, park ranger and public information officer for Indiana Dunes National Lakeshore, said crews didn’t need their scientific equipment to find the second hole, as it was right on the surface of the dune.

Officials aren’t sure yet how these holes are forming, and Rowe says the concept seems to be entirely new to science.

“We do suspect that it may be where Mt. Baldy had covered up a forest of trees [and] that as these trees are rotting out, the trunks of them are rotting out, that they’re leaving behind holes where their trunks once stood,” he said.

The second hole was about five feet deep when crews discovered it, but Rowe says it could have been even deeper beforehand, as there was a lot of loose sand collecting at the bottom.

Last month, six-year-old Nathan Woessner was trapped in the dune for more than three hours while emergency crews tried to dig him out. Doctors initially had to put him in a medically induced coma, but he recovered, and was able to go home from the hospital two weeks later.

Rowe, an employee at the Indiana Dunes for 22 years, admits the entire incident has made him look at Mount Baldy and sand dunes a little differently. Though he says it hasn’t kept him away from them entirely — he and his son camped in Michigan sand dune park last weekend.

Mount Baldy has been closed since the accident, and officials say it will remain closed as the investigation continues.

Lauren Chooljian is WBEZ’s Morning Producer/Reporter. Follow her @laurenchooljian.