Ask Ellen: How did the sand dunes get here?

GRAND RAPIDS, Mich. (WOOD) — They are a gorgeous attraction that draw thousands to the Michigan shoreline each year: the Lake Michigan sand dunes!

Glen Lake over the ripples over Sleeping Bear Dunes_39525

Lake Michigan has a shoreline of 1,640 miles. Our shore of Lake Michigan features some gorgeous dunes. So, how did they get there? That’s today’s kid question from Claire who lives in Holland!

The sand dunes in Lake Michigan all began from really, really, really big chunks of ice called glaciers! Believe it or not, thousand and thousands of years ago, there were massive chunks of ice covering all of West Michigan.

The glaciers were incredibly heavy! When the glaciers slid down over Michigan, they began carving out parts of the ground because they weighed so much!

Over time, the glaciers that were over us slowly retreated. In fact, they advanced and retreated many times, carving out our landscape and creating the giant divot in the ground that began Lake Michigan.

Slowly, water filled up the lake. The glacier helped to carve out the start of the sand dunes, but waves and wind played another big part in creating the rolling mounds of sand you see.

Water usually carries light sand out into the lake. Rocks and pebbles are usually too heavy to be carried very far by the water, so they stack up near the shore.

On stormy days, waves rush onshore and crash higher up on the shore than usual. When this happens, sand gets deposited by the waves back on shore! Dunes are formed and sculpted after the storms fade.

That’s when the sunshine and wind return. Sunshine dries the sand, and wind carries the sand around in swirls. This is what gives our dunes their wind-blown look.

Thank you for the question Clare!

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