| Loess Hills | |
|---|---|
 Loess Hills east of Mondamin, Iowa. | |
 | |
| Location | Western Iowa and Missouri, U.S. |
| Coordinates | 41°48′05″N95°59′42″W / 41.8013°N 95.995°W |
| Designated | 1986 |
The Loess Hills are a formation of wind-deposited loess soil in the westernmost parts of Iowa and Missouri, and the easternmost parts of Nebraska and Kansas, along the Missouri River.
The Loess ( /ˈloʊ.əs/ , /ˈlʌs/ , or /ˈlɛs/ ) Hills are generally located between 1 and 15 miles (2 and 24 km) east of the Missouri River channel. The Loess Hills rise 200 feet (60 m) above the flat plains forming a narrow band running north–south 200 miles (320 km) along the Missouri River. [1] These hills are the first rise in land beyond the floodplain, forming something of a "front range" for Iowa, and parts of Missouri and Nebraska adjacent to the Missouri River. The Loess land formations of Iowa extend north into South Dakota and is a feature of three state Parks in South Eastern South Dakota. Union Grove State Park, Newton Hills State Park and Blood Run State Park.
During the last Ice Age, glaciers advanced into the middle of North America, grinding underlying rock into dust-like "glacial flour." As temperatures warmed, the glaciers retreated and vast amounts of meltwater and sediment flooded the Missouri River Valley. The sediment was deposited on the flood plain, creating huge mud flats. When meltwaters receded, these mud flats were exposed. As they dried, the fine-grained silt was picked up by strong prevailing westerly winds. Huge dust clouds were moved and redeposited over broad areas. The heavier, coarser silt was deposited close to the Missouri River flood plain, forming vast dune fields. The dune fields were eventually stabilized by grass. Due to the erosive nature of loess soil and its ability to stand in vertical columns when dry, the stabilized dunes were eroded into the corrugated, sharply dissected bluffs we see today.
The dominant features of this landscape are "peak and saddle" topography, "razor ridges" (narrow ridges, often less than 10 feet (3 m) wide, which fall off at near ninety-degree angles on either side for 60 feet (18 m) or more), and "cat-step" terraces (caused by the constant slumping and vertical shearing of the loess soil). The soil has a characteristic yellow hue and is generally broken down into several units based on the period of deposition (Loveland, Pisgah, Peoria). Loess is known locally as "sugar clay" because it can be extremely hard when dry, but when wet, loses all cohesion. The Loess Hills of Iowa are remarkable for the depth of the drift layer, often more than 90 feet (27 m) deep. The only comparable deposits of loess to such an extent are located in Shaanxi, China. [1]
Today, the hills stretch from the Blood Run Site in South Dakota in the north to Mound City, Missouri in the south. Loess topography can be found at various points in extreme eastern portions of Nebraska and Kansas along the Missouri River valley, particularly near the Nebraska cities of Brownville, Rulo, Plattsmouth, Fort Calhoun, and Ponca, and the Iowa cities of Hamburg and Sidney. Southeastern South Dakota has three state parks that feature the loess formations: Union Grove State Park, Newton Hills State Park and Blood Run State Park, all of which are south of Sioux Falls. The Big Sioux River separates the South Dakota Loess Hills from the Iowa Loess Hills; in South Dakota, the Loess Hills follow the eastern edge of Brule Creek. The hills are usually no more than 200 feet (61 m) above the Missouri River bottoms. However, in some areas, such as Murray Hill in Harrison County, Iowa, the Loess Hills can rise over 350 feet (110 m) above the adjacent Missouri River floodplain. [2]
The Loess Hills have abundant oak-hickory hardwood forests and some of the last remaining stands of prairie grass in the region. The invasion of prairie and oak savanna areas by woodland species such as red cedar (not native to the Hills) is threatening the stability of the fragile soils, as well as diminishing the native ecosystems found there. The areas of native prairie comprise big bluestem and little bluestem, Indian grass, sideoats grama, and forbs such as yucca, pasque flower and lead plant (false indigo). Many of the prairie species found in the Loess Hills are outside of their normal range of distribution, with plants like spiny-leafed yucca and prickly pear cactus being more common further west, in the Sandhills of central Nebraska. In 1984, a previously undiscovered fern, the Prairie Moonwort, was discovered in the Hills and is thought to be endemic to the Hills.
Common fauna of the modern Loess Hills include white-tail deer, coyote, wild turkey, badger, bobcat, red and gray fox, ringneck pheasant, bobwhite, and red-tailed hawk, some of which were introduced or encouraged by Euro-American settlers. Woodland species are also on the rise in the Loess Hills as the suppression of fire has led to an increase in habitat for forest-dwelling species. Fauna more typical of the pre-settlement Loess Hills, such as the prairie rattlesnake, great plains skink, plains pocket mouse, ornate box turtle and spadefoot toad, are becoming rare and even endangered due to habitat fragmentation as a result of increased development and suppression of fire in prairie remnants and oak savannas. Species such as bobcat have been rebounding, and mountain lions have been recorded in Southwest Iowa in the last decade. Historically, fauna also included American bison, prairie chicken, mule deer, elk, and gray wolf; these were extirpated by the late nineteenth century.
The Missouri River valley had historically been a major migration corridor for birds, however, the channelization of the river and destruction of wetlands has led to a marked decline. The corridor still boasts one of the best areas to view raptor migrations on the continent. As air masses move off the Great Plains, they sink into the Missouri River valley. The prevailing winds across the floodplain then hit the sharp rise of the Loess Hills, creating thermal updrafts that raptors use to make their way to and from breeding grounds. Raptors can often be viewed forming "kettles", where many birds will create a funnel-like formation as they utilize the same thermal. Typical species found during the months from September to December include red-tailed hawk, sharp-shinned hawk, peregrine falcon, ferruginous hawk, Swainson's hawk, Cooper's hawk, osprey, northern harrier, American kestrel, and bald eagle. In all, 20 species of raptor have been identified in a single season since the Hitchcock Nature Center HawkWatch started, with a record count of 16,000 birds in one season in 2005.
Broken Kettle Grasslands Preserve in the northern Loess Hills is home to Iowa's only population of nesting black-billed magpies and home to the last remaining known population of prairie rattlesnake in Iowa. [3]
The Loess Hills Scenic Byway affords many scenic views from Westfield, Iowa, and to Hamburg. While much of the landscape is held in private ownership, thousands of acres of public land exist in state and county parks, wildlife areas and preserves. The Nature Conservancy also owns several preserve areas in the Hills which are open to the public, including Broken Kettle Grasslands Preserve—the largest contiguous tract of native prairie left in Iowa. [4] The Loess Hills State Forest is located in west-central Iowa in Harrison and Monona counties. It comprises four units totaling 10,600 acres (43 km2), and offers hiking, backpacking, picnicking, and fishing opportunities. Preparation Canyon State Park, located near Pisgah in Monona County, is a less developed park in the middle of the Loess Hills State Forest. It has 344 acres (1.4 km2) including what was once the Mormon village of Preparation. Backpacking trails lead to hike-in campsites. Two major state parks anchor the north and south end of the range—Waubonsie in the south and Stone in the north, both offer camping and a variety of other amenities. Hitchcock Nature Center is operated by the Pottawattamie County Conservation Board and features a lodge with raptor viewing platform and observation tower, from which one has striking views of the Hills, the Missouri River valley, and the skyline of downtown Omaha, Nebraska. Hike-in camping is also available at this location. Two National Natural Landmarks are located in the Loess Hills. The Little Sioux/Smith Lake Site contains 2,980 acres (12 km2) and is perhaps the best example of the unique topography produced by large deposits of loess soil. The 7,440-acre (30 km2) Turin Site of the Loess Hills National Natural Landmark is located just outside Turin and also contains the Turin Man prehistoric archeological site. [5]
The Loess Hills have a rich archaeological heritage. The hills around Glenwood, in Mills County, were inhabited by the Glenwood culture, an eastern extension of the Nebraska Phase of the Woodland period. The Glenwood Culture lived in the area from roughly 900 A.D. to 1300 A.D. and built hundreds of earth lodges in the region, farming the rich valley bottoms and cultivating native plants from the surrounding hills. An earth lodge replica has been reconstructed in Glenwood Lake Park, and the Mills County Museum, also located at the park, houses an excellent collection of artifacts collected by renowned amateur archeologist Paul Rowe.
The city of Council Bluffs, Iowa (originally "Kanesville") derives its name from the hills based on the Lewis and Clark first formal "council", or meeting, with Native Americans in 1804, although the meeting with the Oto and Missouri tribe actually took place on the Nebraska side of the Missouri River at Fort Atkinson. Sgt. Charles Floyd, the only fatality of the Lewis and Clark Expedition, is buried on a bluff in the Loess Hills in what is now Sioux City, Iowa.
In 1853, Mormon elder Charles B. Thompson split off from the main wagon train to Utah. He initially led 50 to 60 Mormon families to Kanesville. Thompson and a few other men then chose an area called Monona ("peaceful valley"), where they founded the town of Preparation, named for "School of Preparation for the Life Beyond." Realizing the valley's wealth as a farming region, Thompson used his newspaper to report a message "from a spirit" directing the Mormon people to turn over all deeds and possessions to Thompson, who changed his name to "Father Ephraim". In 1856, the people asked for the return of their property; Thompson refused and they decided to lynch him. Thompson escaped the mob by hiding in an attic in Onawa. He then fled Iowa. [6]
On August 12, 1859, Abraham Lincoln ascended the hills at Cemetery Hill at Fairview Cemetery in Council Bluffs while being briefed on possible locations for the First transcontinental railroad.
Loess soil also forms the Arikaree Breaks in northwest Kansas, and the Mississippi-Yazoo "Bluff Hills" near Vicksburg, Mississippi. A large region of Nebraska to the south and east of the Sandhills is covered with loess. Deep loess deposits are also found in the Rhine River valley in Germany. Crowley's Ridge in southeastern Missouri and northeastern and eastern Arkansas is made up of loess soil. The word loess is derived from the German for "loose or crumbly."
The Great Plains, sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located just to the east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. It is the western part of the Interior Plains, which also include the mixed grass prairie, the tallgrass prairie between the Great Lakes and Appalachian Plateau, and the Taiga Plains and Boreal Plains ecozones in Northern Canada. Great Plains or Western Plains is also used to describe the ecoregion of the Great Plains, or alternatively the western portion of the Great Plains.
Council Bluffs is a city in and the county seat of Pottawattamie County, Iowa, United States. It is the most populous city in Southwest Iowa, as well as the third largest and a primary city of the Omaha-Council Bluffs Metropolitan Area. It is located on the east bank of the Missouri River, across from Omaha, Nebraska. Until about 1853 Council Bluffs was known as Kanesville. Kanesville was the historic starting point of the Mormon Trail. Kanesville is also the northernmost anchor town of the other emigrant trails because there was a steam-powered boat which ferried the settlers' wagons and cattle across the Missouri River. In 1869, the first transcontinental railroad to California was connected to the existing U.S. rail network at Council Bluffs.
Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type. Temperate grassland regions include the Pampas of Argentina, Brazil and Uruguay, and the steppe of Ukraine, Russia and Kazakhstan. Lands typically referred to as "prairie" tend to be in North America. The term encompasses the area referred to as the Interior Lowlands of Canada, the United States, and Mexico, which includes all of the Great Plains as well as the wetter, hillier land to the east.
Crowley's Ridge is a geological formation that rises 250 to 550 feet (170 m) above the alluvial plain of the Mississippi embayment in a 150-mile (240 km) line from southeastern Missouri to the Mississippi River near Helena, Arkansas. It is the most prominent feature in the Mississippi Alluvial Plain between Cape Girardeau, Missouri, and the Gulf of Mexico.
The tallgrass prairie is an ecosystem native to central North America. Historically, natural and anthropogenic fire, as well as grazing by large mammals provided periodic disturbances to these ecosystems, limiting the encroachment of trees, recycling soil nutrients, and facilitating seed dispersal and germination. Prior to widespread use of the steel plow, which enabled large scale conversion to agricultural land use, tallgrass prairies extended throughout the American Midwest and smaller portions of southern central Canada, from the transitional ecotones out of eastern North American forests, west to a climatic threshold based on precipitation and soils, to the southern reaches of the Flint Hills in Oklahoma, to a transition into forest in Manitoba.
The Dissected Till Plains are physiographic sections of the Central Lowlands province, which in turn is part of the Interior Plains physiographic division of the United States, located in southern and western Iowa, northeastern Kansas, the southwestern corner of Minnesota, northern Missouri, eastern Nebraska, and southeastern South Dakota.
The Geography of North Dakota consists of three major geographic regions: in the east is the Red River Valley, west of this, the Missouri Plateau. The southwestern part of North Dakota is covered by the Great Plains, accentuated by the Badlands. There is also much in the way of geology and hydrology.
Buffalo Ridge is a large expanse of rolling hills in the southeastern part of the larger Coteau des Prairies. It stands 1,995 feet (608 m) above sea level. The Buffalo Ridge is sixty miles (97 km) long and runs through Lincoln, Pipestone, Murray, Nobles, and Rock counties in the southwest corner of Minnesota, and Minnehaha, Moody, and Lincoln counties in southeast South Dakota.
In the US state of Iowa, Interstate 29 (I-29) is a north–south Interstate Highway which closely parallels the Missouri River. I-29 enters Iowa from Missouri near Hamburg and heads to the north-northwest through the Omaha–Council Bluffs and the Sioux City areas. It exits the state by crossing the Big Sioux River into South Dakota. For its entire distance through the state, it runs on the flat land between the Missouri River and the Loess Hills.
South Dakota is a state located in the north-central United States. It is usually considered to be in the Midwestern region of the country. The state can generally be divided into three geographic regions: eastern South Dakota, western South Dakota, and the Black Hills. Eastern South Dakota is lower in elevation and higher in precipitation than the western part of the state, and the Black Hills are a low, isolated mountain group in the southwestern corner of the state. Smaller sub-regions in the state include the Coteau des Prairies, Missouri Coteau, James River Valley, and the Dissected Till Plains. Geologic formations in South Dakota range in age from two billion-year-old Precambrian granite in the Black Hills to glacial till deposited over the last few million years. South Dakota is the 17th-largest state in the country.
The Missouri River Valley outlines the journey of the Missouri River from its headwaters where the Madison, Jefferson and Gallatin Rivers flow together in Montana to its confluence with the Mississippi River in the State of Missouri. At 2,300 miles (3,700 km) long the valley drains one-sixth of the United States, and is the longest river valley on the North American continent. The valley in the Missouri River basin includes river bottoms and floodplains.
The geography of Iowa includes the study of bedrock, landforms, rivers, geology, paleontology and urbanisation of the U.S. state of Iowa. The state covers an area of 56,272.81 sq mi (145,746 km2).
Paha are elongated landforms composed either of only loess or till capped by loess. In Iowa, paha are prominent hills that are oriented from northwest to southeast, formed during the period of mass erosion that developed the Iowan surface, and they are considered erosional remnants since they often preserve buried soils. Paha generally rise above the surrounding landscape more than 6.1 metres (20 ft). The word paha means hill in Dakota Sioux. Well known pahas include the hill on which the town of Mount Vernon, Iowa developed, Casey's Paha in Tama County, Iowa, and the Kirkwood Paha, home of Kirkwood Community College's campus. These features are found in other regions of the United States and in Europe, where they are known as greda.
Waubonsie State Park is a state park in Fremont County, Iowa, United States, located in the Loess Hills region. It is named for Chief Wabaunsee of the Potawatomi people.
The Missouri River Activities Conference is a high school athletic and activities conference whose members are located in either the Sioux City Metropolitan Area or the Omaha-Council Bluffs Metropolitan Area, both located along the Missouri River on the border of western Iowa.
The environment of Iowa has been heavily affected by agricultural production since it became a U.S. state in 1846. However, there remain natural areas in Iowa that reflect a wide varieties of environmental niches.
U.S. Highway 75 (US 75) is a United States Highway in northwestern Iowa. It begins at the Missouri River on a bridge with Interstate 129 (I-129) and US 20. Immediately upon landing in Iowa from Nebraska, I-129 ends at an interchange with I-29. US 20 and US 75 continue around Sioux City on a four-lane expressway until US 20 exits to the east. US 75 heads to the north-northeast, parallel to the Floyd River, until Le Mars. There, Iowa Highway 60 (Iowa 60) continues northeastward on the expressway while US 75 heads due north. Near Hull, it is briefly overlapped by US 18. It leaves the state and enters Minnesota north of Rock Rapids.
The Western Corn Belt Plains is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in seven U.S. states, though predominantly in Iowa.
Loess Hills District is an American Viticultural Area (AVA) located in western Iowa and northwestern Missouri established on April 4, 2016 by the U.S. Department of Treasury’s Alcohol and Tobacco Tax and Trade Bureau (TTB). TTB received a petition from Shirley Frederiksen, on behalf of the Western Iowa Grape Growers Association and the Golden Hills Resource Conservation and Development organization proposing the establishment of the “Loess Hills District.” The district is a long, narrow north–south orientated swath of land along the Big Sioux and Missouri Rivers, covering 12,897 square miles from Hawarden, Iowa, to Craig, Missouri. There are approximately 66 commercially-producing vineyards covering a total of 112 acres (45 ha) distributed throughout the AVA, along with 13 wineries. Loess Hills District is not a sub-region within any established AVA.
