Largest freshwater dune system in the world
The Eastern shore of Lake Michigan is home to the largest freshwater dunes systems in the world. From the Indiana Dunes along the southernmost shore to the low dunes in the U.P. along US Highway 2, dune formations dot the coastline with amazing arrays of ecosystems unique to this location.
Old Parallel Dunes
As the water level adjusts over time, often the sand is left to the mercies of the lake wind. After a while, sand will pile into low hills called parallel dunes or beach dunes. Along Lake Michigan, these dunes date back four thousand years ago when the water level was thirty feet higher than it is today.
Over time parallel dunes are eroded away and reshaped into a series of deep U-shaped sand traps. These are called Parabolic Dunes and offer a unique look into the sands. Their irregular shape and formation style make them a must-see on any trip to the eastern side of Lake Michigan.
Parabolic Dunes are formed by things called blowouts. Blowouts happen when something disrupts the plant life and vegetation is disrupted by some event and the sand becomes loose. As the wind erodes the sand, it can cover up entire forests and eco-systems, and uncover others that had long been forgotten.
A perched dune forms where a “glacial moraine” is present. A moraine is just a deposit of sand, gravel, and stone that was left in a ridge by a retreating glacier. Sand is blown up the windward side. It collects as it spills over into the leeward side, creating a unique visual spectacle.
As you travel from the lakeside to the inland of Michigan, you’ll pass through several very distinct ecological zones. You’ll see a quick change in plant life and plants that are able able to thrive in each environment. A plant cannot take over the other zones simply because it won’t survive too far in either direction from where it found its foothold.
The beach offers a unique, if apparently barren, biologic view. Waves, ice, and the wind continuously scour this land, making it nearly impossible for plants to ever gain a foothold there. Sometimes there are some stubborn beach grasses, but they don’t last long in the conditions of the beach.
Once you pass the high water mark, you enter an ecological zone known as the foredune. Only very few very hearty plants can survive here. The light color of the sand reflects the sun’s heat back into the breeze, turning the area into an oven in the hot summer, and only very stubborn broadleaf plants and grasses can tolerate this kind of heat.
Moving farther from the shore of Lake Michigan, you’ll find that the winds die down, and the sand is more stable than the foredunes or beach. This area is called the Back dune, and the naturally hilly terrain helps it have a variety of little microhabitats. The north facing dunes favor trees, shrubs, and cool preferring wildflowers, while the south facing dunes are very different.
Sleeping Bear Dunes
Probably the most famous of the dune systems in the US is the Sleeping Bear Dunes. Almost everyone has heard the story of the Mama bear waiting for her cubs after swimming across the lake to escape a wildfire. The Sleeping Bear Dunes are perched dunes left behind when the glaciers carved out the lake. They’re perfect for a sightseeing trip with kids.