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Indiana Dunes sinkhole that swallowed boy ‘still a mystery’

Crews work beach Mount Baldy Michigan City Ind. Friday July 12 2013.  | Taylor Irby~For Sun-Times Media

Crews work on the beach at Mount Baldy in Michigan City, Ind., Friday, July 12, 2013. | Taylor Irby~For Sun-Times Media

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Updated: August 20, 2013 6:35AM



An official with Indiana Dunes National Lakeshore said Thursday it could be at least two weeks before the necessary ground-sensing equipment will be available in the ongoing effort to determine why a portion of Mount Baldy collapsed July 12, burying 6-year-old Nathan Woessner in 11 feet of sand.

“It’s still a mystery. It’s amazing,” said Bruce Rowe, the park’s public information officer.

Mount Baldy, the nearby parking lot, and surrounding trails remain closed. A safety protocol, to guide researchers and park staff as they investigate the collapse, should be complete this week.

“Nobody has physically been on that dune, at least not legally,” since July 12, Rowe said, adding park staff patrols the area and additional signs are going up along the beach to keep the public off the dune.

Park staff reached out to geologists about the matter, as well as officials at other state and national parks with shifting dunes like Mount Baldy.

One of the theories being discussed as a cause of the sinkhole is that a decomposing tree under the surface shifted, which remains a possibility, said Erin Argyilan, an associate professor in geosciences at Indiana University Northwest.

Argyilan was on Mount Baldy a couple hours before the collapse, doing research on creating a 3-D model of the dune and how it is changing. She was on the beach when the collapse occurred, and met with Michigan City police and fire officials Thursday morning as they, too, tried to get a better grasp of what happened.

“Obviously the way Mount Baldy looks today is significantly different than the way it looked 50 years ago, or even 75 years ago,” she said, adding she has studied pictures and maps of the dune from those time periods. “The site where the boy was found would have been in forest.”

The dune, which is about 126 feet high, also could cover man-made structures that might have collapsed, including a well or a building, and caused the hole, she said. Even recent heavy rains may have contributed in some way.

Mount Baldy is shifting for a number of reasons, Argyilan said, including from hikers who displace sand and even from the construction of the pier at Washington Park in the 1830s, which captured sand that otherwise would have been destined for the dune.

“Those are all things we’ll have to add up in the pieces of science to see if they make sense,” she said.

Ground-sensing equipment will be used for a conductivity survey of the entire 43 acres of Mount Baldy, Rowe said. That will show any anomalies below the surface, and then ground-penetrating radar will be used for high-resolution images of those anomalies.

The equipment and testing are expensive, though Rowe declined to give a cost estimate.

Officials at nearby Indiana Dunes State Park, which also has dunes that are popular with hikers and boasts Mount Tom, the tallest dune in the state, are keeping a watchful eye on what happens at the national lakeshore.

Staff from that park looked for visual clues Monday to see if anything was amiss in the wake of what happened on Mount Baldy.

“That was not anything we had done before,” said park manager Brandt Baughman, adding it’s hard for his park to know what to do in terms of preventative measures until officials find out what happened at Mount Baldy. “We hope once the lakeshore is able to determine that, that may help us keep an eye out for anything like it.”



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