How were the dunes at Sleeping Bear formed?
Sleeping Bear Dunes was made a national lakeshore because it is the largest freshwater dune system in the world. These landforms weren’t created overnight, however. Millions of years ago large sheets of ice, or glaciers, covered Michigan. These chunks of ice plowed through the ground causing rocks and other materials to pile up around the sides. When the glaciers melted this leftover material is what formed the dunes. Over the years, sand has piled on top of these formations causing them to grow even higher. This is what we are seeing when we look at Sleeping Bear Dunes today.
Dunes are constantly growing and changing. Wind coming off of Lake Michigan is always moving sand to different places. With the freezing and thawing of winter, and the continual sand being piled higher and higher, sandslides can occur changing the dunes significantly.
Last updated: July 10, 2020