The Dunes

Origin of the Dunes

Lake Michigan originally formed around 11,000 years ago when the Wisconsin Glacier began to slowly melt and recede north. As its melt rate fluctuated, the glacier left behind a variety of different natural landscapes including rolling hills, wetlands, Lake Michigan, and the dunes ridgeline.

Near the Lake Michigan shoreline, younger dune complexes show the many stages of plant succession. Wide-open beaches, grass-covered dunes, and blowouts transition into woody shrub vegetation and forested dunes. Moving further inland, older dune complexes can be seen with well-established oak forests.

Types of Dunes

There are two types of dunes: foredunes and blowout dunes. 

Foredunes

Foredunes are close to the beach and covered in vegetation like marram grass. This makes for a more stabilized dune and allows even more plant life to thrive.

Blowout dunes

Blowout dunes are caused by intense winds that rip the dunes apart. The loose sand makes a “living dune,” that can move up to several feet every year. Blowout dunes can sometimes be the result of unapproved trails, or social trails, which gradually turn into bigger and bigger areas of sand. So, please check your map to make sure you are on approved trails only!

Indiana Dunes FAQ

Have more questions? Check out our FAQ page where we’ve answered frequently asked questions about the Indiana Dunes National Park and Indiana Dunes State Park.

Beach Closures and Safety

Tips to keep you up-to-date on beach safety, closures, and more.