NEAR SIOUX CITY, Iowa (KTIV) -
The Loess Hills are up to 15 miles wide and about 200 miles long and they cover 640,000 acres of land. Running north of Sioux City all the way down to St. Joseph, Missouri.
And it makes a unique micro-environment unlike anything else in the Western World.
It's a type of soil that is very common across the United States and around the world. But here in Western Iowa, what makes our Loess Hills so special are their thickness. Those many layers of loose fine, powdery material formed during the last glacial period.
"The heavier sediments dropped out first and aligned along what is now the Missouri River Valley on the eastern side. So Loess deposits, really run about 220 miles here in Iowa from North of Sioux City at Westfield Iowa to the southern part of Iowa below Hamburg and into just a touch of Missouri," Dawn Snyder, the Director of the Dorothy Pecaut Nature Center.
And within this very narrow land formation, there's a microclimate.
"The hills themselves have such a hot and unique and dry temperature within the western slopes. You've got the summer sun and the winds. They are really vulnerable to high heat and high winds. So you've got animals and plants that are on the edge so to speak and many of those species are western species, that are desert like species," Snyder said.
Plants like the Yucca or prickly pear cactus and the Prairie Rattlesnake survive here, where they would normally live 200 miles farther west. And with Loess being so fine, it does erode three to five times faster than many other types of soil.
"A good example would be War Eagle's Grave site overlooking the Big Sioux and the Missouri River and that site has slumped over years naturally. But it also has been accelerated because of the railroad and the interstate traffic and that type of thing," Snyder said.
Snyder says the hills are always naturally changing but if people have enough forethought, they will be around to enjoy for years to come.
"I encourage people to get outside and enjoy the Loess Hills and realize that they National Treasures," Snyder said.
Loess is actually a German word meaning loose or crumbly.
The only deposits in the world deeper than those in Western Iowa are in China.
Deposits can reach up to nearly 300 feet.
