Loess Hills

[Abby Brown] Kari, the views at Stone State Park are just fantastic and it has a lot to do with the Loess Hills. Can you tell me more about them?

[Kari Sandage] Sure! Yeah the Loess Hills are very unique because there are only two places in the world where you can find Loess Hills. One place is here, in Sioux City, Iowa and in China. Yes, so the Loess Hills were formed thousands of years ago and that all starts back to the time of the glaciers.

[Abby] Okay.

[Kari] And glaciers are basically rivers of ice, so they are constantly in motion. And when they move, they're really heavy, so they carve into the landscape below. And that is called erosion. And so when these glaciers move they erode the ground beneath them and they create this thing called a glacial flour; which is basically a bunch of sediment and dirt along the way.

[Abby] Okay so there's still glaciers on top, so this is all happening under the glacier?

[Kari] Under the glaciers.

[Abby] And then what happens next?

[Kari] And then after that, oh it takes quite a while for this to happen, but they carve away into the earth, creating river valleys. And so we are next to the Missouri River Valley.

[Abby] Yep.

[Kari] And then during the winter the glaciers will be frozen, but during the summer time the glaciers melt.

[Abby] Yes.

[Kari] Yep, so just like in your backyard the snow doesn't last all summer so the glaciers will melt and will leave behind the silt or the sediment, all that stuff the glacier picked up.

[Abby] Has been carved off of the land?

[Kari] Yes. Okay so that will be there on the ground, exposed. And then, back thousands of years ago it was super super windy so the wind on the other side of the Missouri River carries it over to our side of the Missouri River and, since it's much lighter, it'll go a little bit farther than the soil that drops out and it lands in this one long line along the Missouri River.

[Abby] Okay, and how deep are the Loess Hills?

[Kari] They can be around 200 feet deep.

[Abby] Wow! And so they've been here for thousands of years, but erosion does continue to change the landscape even after the glaciers are gone with wind and water, so how have those elements affected the hills over time?

[Kari] So, like you said, the wind in the water will carve the Loess Hills into the shapes that we see today. So no two Loess Hills look the same, they all look very very different, and that's due to erosion.

[Abby] Okay, what about the future of the Loess Hills? What's going to happen if erosion continues to change the hills?

[Kari] We could see some more erosion and maybe some, you know, decrease in the deepness of the Loess Hills.

[Abby] Okay and we want to prevent that, right? What's the best way to keep that from happening?

[Kari] Just to kind of appreciate how unique these are. They're in your backyard and they're beautiful and we just, you know, need to appreciate them.

[Abby] Yeah! And in a place like this, at a state park where it's protected, people have to be really careful about how they treat the land.

[Kari] Right.

[Abby] Kari, thank you so much for that great explanation about the Loess Hills. We had a great time investigating today!

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