One of Indiana Dunes National Lakeshore's biggest attractions could remain closed into the fall. Acting Superintendent Garry Traynham says deep holes at Mount Baldy remain a mystery and pose a “serious risk.” The U.S. National Park Service, Indiana University and Indiana Geological Survey officials are lining up “a more comprehensive investigation.” April 24, 2014

News Release

NORTHWEST, Ind. – Despite the use of ground penetrating radar, and data gathering at two additional holes that have appeared since last July, scientists still don't know the cause of the holes at Mt. Baldy in Indiana Dunes National Lakeshore. Additional research will be conducted this summer and may last into the fall. To ensure the public's safety, Mount Baldy, its parking lot, trail, and beach in front of the dune will remain closed to all vehicular and pedestrian access while the investigation continues.

“Mount Baldy is one of the most visited sites in the national lakeshore, attracting thousands of visitors each year” said Acting Superintendent Garry Traynham “but the continued development of these holes in the dune surface poses a serious risk to the public. Our first obligation must be to the welfare of our visitors who are here for an enjoyable outing.”

Ground penetrating radar studies by the Environmental Protection Agency (EPA), have identified a large number of anomalies below the dune's surface, but analysis by scientists from the National Park Service, Indiana University and the Indiana Geological Survey have not yielded answers on how these holes form. One such hole nearly cost a 6-year old Illinois boy his life last summer at the national lakeshore's most popular sand dune.

The two additional holes and a number of depressions have been found during the ongoing investigation and continued monitoring of the dune. Scientists report that the holes are short-lived, remaining open for less than 24 hours before collapsing and filling in naturally with surrounding sand.

Scientists are now preparing for a more comprehensive investigation of the dune this summer. This study will include mapping of openings, depressions, and anomalous features, the use of multispectral Ground-Penetrating Radar (GPR) and coring to develop a better understanding of the overall internal architecture of the dune, and detailed GPR and coring of some of the anomalies identified in the EPA report.

During the research work, the park's resource managers will continue planting marram grass on portions of Mt. Baldy where the native dune grass used to grow. The extensive root system of the grass holds sand in place and may also help prevent holes from opening up on the dune's surface.

All other beach access areas within the national lakeshore are currently open and visitors are asked to stay on the established trails to prevent erosion and subsequent resource damage.

For more information, and to view the EPA's Geophysical Survey Report, a Core Study, photos, video, and graphics on the Mount Baldy research, go to the national lakeshore's website at:

Indiana Dunes National Lakeshore is part of the National Park Service. More than 20,000 National Park Service employees care for America's 401 national parks and work with communities across the nation to help preserve local history and create close-to-home recreational opportunities. Learn more at

Source: Indiana Dunes National Lakeshore

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