Sand Dunes and Moraines

Published: June 12th 2018
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Sleeping Bear Dunes National Lakeshore, Empire, Michigan

We’ve already been to several parks that focus on sand dunes, and each one has a unique twist. White Sands, in New Mexico, is made up of small grains of gypsum giving it the white color and keeping it from getting hot even in triple digit temperatures. Great Sand Dunes, in Colorado, has huge sand dunes nestled into the corner of a Rocky Mountain. Indiana Dunes, at the southern tip of Lake Michigan, serves as special place for the urban citizens of Chicago, Gary, and other industrial cities of the area.

Here at Sleeping Bear Dunes, far from mountains and big cities, the dunes are unique because of how and where they were created - on the tops of glacial moraines. When the last glaciers began their retreat, 12,000 years ago, after carving out the valleys that created the Great Lakes, they left behind mountains of debris. Silt, sand, rocks, and boulders that had been pulverized from the movement of solid ice, up to two miles thick, stopped moving forward as the temperatures warmed and the ice melt. Without the carrying force of the glacier, they simply dropped where they were leaving small mountains of material in new, and sometimes strange locations. We already saw in Ohio, that the deposits filled in old river valleys, diverting rivers into new paths and establishing a continental divide of sorts that would serve as the main challenge in building the canals that connected the Great Lakes region with the Mississippi Valley.

Here on the northeastern shores of Lake Michigan, the retreating glacier left a lateral moraine - a massive conglomerate of rocks, sand, and silt that reaches as high as 450 feet above the current sea level of Lake Michigan. Then the winds, predominantly from the west and south, carried sand particles from what is now Wisconsin across the lake. As the wind hit the moraines, the only place it could go was up, lifting the sand up to the top of the moraine. Once on top, the wind slowed, lost carrying capacity, and deposited sand grains. Grain by grain, and over the last ten thousand years, sand dunes were built up on the top of the glacial deposits.

A thousand years or more ago, ancestors of the Chippewa Indians created an origin story to explain this area. A mother bear and her two cubs left the Wisconsin land mass because of dwindling food supplies. Seeking a new home, the bears began to swim across Lake Michigan. But it was a huge lake and the bears got increasingly tired. The cubs couldn’t make the swim, drowned in the lake, and sank to the bottom. The mama bear, made it across, but was totally exhausted. She climbed to the top of the shore and waited for her cubs. There she witnessed her two dead children bob to the surface where they formed North and South Manitou Islands. Unable to save her cubs, and exhausted from the swim, she lay down on the high shore and went to sleep. She has been there ever since.

The actual Sleeping Bear Dune doesn’t look much like a sleeping bear anymore. Human efforts to carve a path through it actually ended up stripping the area of its defining tree cover. Without roots to stabilize it, the sand has been eroded away and the sleeping bear is just a remnant of what it used to be. Still, it makes for an imaginative story.

We began our exploration of this park yesterday by doing the Pierce Stocking Scenic Drive. Now, I’m not real clear who he was, but he seemed to be involved in real estate in this area way back before the park was created. He constructed a drive through the area and took tourists on it to show them what was here. Parts of that drive have been preserved, and improved, by the park to create a 7.5 mile introduction to this park that really is a perfect way to see what’s going on. The drive is a one-lane road but has pullouts at various places with numbered signs that correspond to descriptions available in the park newspaper. It also has parking lots where you can get out and, after a short hike, see some pretty spectacular views.

At the third stop, you park the car and take a short hike to a viewing platform that looks out over the four-square mile dune field. In the distance is Lake Michigan and the Manitou Islands. You can’t help but get a maritime sense of things here. The huge size of these lakes makes it easy to think you are at the ocean. There is even a lighthouse visible on one of the islands. It reminded me a lot of the Outer Banks in North Carolina.

On the next stop there is an opportunity to take a hike through the dunes, the Cottonwood Trail. it is only a mile and a half in length, but there is no shade and walking in sand is not as easy as walking on a hard path. There is a need for sunscreen, a hat, and water. But we took the girls on this hike and, tired and a bit overheated, they made it back to the car with us. With all those new smells, how could they not enjoy it. We enjoyed it too, seeing different stages in the life of the dunes from raw, unsecured dune, to a cottonwood forest of sorts that seemed to be a bit more stable. If you can only do one hike in this park, this might be the best choice.

Further along the drive, there are stops in thick beech-maple forests. This is more of the climax ecology representing the most evolved area of the dunes. There is also one section of the drive passing through a pine forest. This was an early conservation effort by people to replenish the original

Lake Michigan and the Dune Field
forests cut down for lumber a century or two ago. At another stop, you look out over two lakes, formed by glacial streams that were eventually cut off by sand bars. Both interesting and gorgeous.

The highlight of the scenic drive, though, was at stops 9 and 10. Here you park the car and take a short hike to the western edge of the dune field. From the top, you look down the dunes and the moraine to the shores of Lake Michigan. There is not much to prepare you for this view and I’m not sure the pictures will help. Out in the distance is the blue stillness of Lake Michigan, punctuated by a few clouds. Some 50 miles away is Wisconsin, although the curvature of the earth makes that impossible to see. But the real kicker is to look down to the actual edge of the lake - 450 feet down a very steep hill. As you study this hill, you realize that this is not a sand dune - this is what’s left of the glacial moraine. It is composed of a conglomeration of rock and sand particles, most of them too big to be lifted by the wind. This mountain was built by glaciers, and merely finished by wind.

There is a sign at the top warning, but not preventing, people from trying to descend the mountain to the beach below. It tells them that while it seems like running down the thing might be fun, you have to return - and that might not be so much fun. The sign says to expect at least a 2 hour effort. For some younger folks, it might not take quite that long. There were several younger people attempting the climb up and I give them credit for energy, although I’m not sure it would be worth the challenge. The sign also warns that the cost for having to be ‘rescued’ if you can’t make it up, is substantial.

Walking another 600 feet out, there is a terrific overlook spot that places you above the entire dune field and in view of the lake and the islands. From there you can see the name-sake dune, although it definitely doesn’t look much like a bear anymore. Still, though, this is where you gain a keen appreciation for the beauty of this park.

After the drive, and the hike, we were all fairly tired. We took the girls back to the trailer and then drove back down to Frankfort for a lunch at Stormcloud Brewery. They had some interesting brews including one with a taste of coconut. I had a cherry-BBQ brisket sandwich, and Joan had a pizza. After lunch, we went back to the trailer and took a late afternoon nap.

Once again, we are astounded and a bit overwhelmed by our park.

Additional photos below
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450 Feet Down to the Shore. Those are People Down There

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