Minimize Sleeping Bear Dunes National Lakeshore

The Ojibwa tribe has a heart-rending legend that explains how the dunes of Sleeping Bear Dunes National Lakeshore and two nearby islands in Lake Michigan formed.

The legend says that long ago, a mother bear and two cubs were driven into the lake by the encroachment of fires on land. After hours of swimming, the mother bear reached the far shore of the lake. But when she turned around to check on the progress of her cubs, she saw nothing. Both of them had slipped beneath the lake surface and disappeared. The mother bear spent days staring out across the lake in the hopes they would eventually swim ashore. But after weeks of waiting, the heartbroken mother bear laid down to sleep on a bluff overlooking the lake and never woke up. In recognition of her suffering, the Ojibwa say a powerful spirit covered her with sand and made her two cubs rise above the water as North and South Manitou island.

Geologists have a different way of explaining the formation of the dunes and the two islands. The geological story begins with ice. During the last Ice Age, glaciers spread southward from Canada, burying the area under thick sheets of ice. When the glaciers eventually retreated about 12,000 years ago, they deposited large piles of sand and rock debris, creating the hilly terrain visible along the lakeshore today. Sand deposited by glaciers is the main ingredient for the "perched dunes" located on bluffs relatively high above the water level. Meanwhile, winds also built dunes at lower elevations from beach sand as the lake's water levels fluctuated.

This image, acquired by the Operational Land Imager (OLI) on Landsat 8 on 17 June 2016, shows Sleeping Bear Dunes National Lakeshore, which spans 56 kilometres (35 miles) along the eastern shore of Lake Michigan.

View the full resolution image.

Credit: NASA Earth Observatory image by Joshua Stevens, using Landsat data from the U.S. Geological Survey

Sleeping Bear Dunes National Lakeshore

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