MICHIGAN CITY, Indiana — Scientists are still confounded 13 months after a then-6-year-old boy was nearly buried alive in a popular sand dune in northwest Indiana, saying they found a sixth hole this week as they moved high tech gear into place to try to conduct further testing on what is causing the holes.
Three geologists who are the principle investigators arrived Monday and hope to use radio waves and core samples they collect in the next week to amass enough data to eventually build a three-dimensional map of a section of the 126-foot-high Mount Baldy to see if they can determine what is causing the holes.
Bruce Rowe, spokesman for the Indiana Dunes National Lakeshore, said Mount Baldy will remain closed until more is known.
"We want to let the science do the talking before we do any management decisions as to whether to open Mount Baldy," Rowe said. "We have a great desire to reopen it. It's one of the most popular areas in the lakeshore. But we want to make sure we understand what's going on from a geological standpoint so we can make the proper decisions."
The geologists say what they are finding out is changing what they thought they knew about the properties of sand dunes.
Indiana University Northwest associate geology professor Erin Argyilan was at Mount Baldy conducting a wind study on July 12, 2013, when Nathan Woessner of Sterling, Illinois, became trapped more than three hours and couldn't believe he had fallen into a hole.
"It's disturbing because everything I knew about dunes led me to confusion. There's no way that something like this should have happened. I've never read or heard about voids in dunes," Argyilan said.
One of the working theories is that the holes might be related to decaying trees or rotting man-made structures that the dune has covered over the years, although Argyilan said other possibilities have not been ruled out. But she said they have heard about smaller holes being reported at Oregon Dunes National Recreation Area in far western Oregon and officials there say they are from decaying trees.
Todd Thompson, assistant director of the Indiana Geological Survey, said that didn't make sense to him at first.
"Because where does the tree go? If it's buried inside this dune and it rots, isn't there still a mass there? It's got to go somewhere," he said.
Argyilan is using data compiled last year by crews using ground-penetrating radar to check out anomalies in the dune to see if trees or structures are to blame.
The latest hole, about 7 inches wide and about 4½ feet deep, was discovered Wednesday in a spot where Thompson had previously stepped while moving equipment.
"I didn't notice it," Thompson said. "I just continued to walk on and it probably collapsed out after I went by."
Most of the holes have been smaller. Argyilan estimates most of the holes have been about 2 inches wide. She said the hole found Wednesday was the deepest they've found. The previous deepest was about 3 feet deep.
The holes are difficult to measure, though, because by the time scientists return to measure them they have begun to fill with sand, Argyilan said.
Thompson said the $90,000 study, funded by the National Park Service grant, calls for an initial report in three months, a preliminary report in six months and a final report in a year.
It's too early to say whether there is any way to fix the problem, he said.