Nature & Science
The Minuteman changed the northern plains, but clearly the missile system was one small moment in the region's far broader natural history. Western South Dakota is a land rich in geological and natural features.
Geology of Western South Dakota
The seas that once covered South Dakota's Western Plains deposited limestone and sandstone overlain by soft Pierre shale. As the shale eroded through water and wind action, the rolling terrain in the Western Plains emerged, leaving short-grass plains mixed with eroded river valleys. The Badlands lie within the Great Plains. The striking landscape of the Badlands emerged from the process of erosion caused by water and wind, which created tall spires of sedimentary rock and exposed rich fossil deposits.
Southwestern South Dakota's climate is semiarid, characterized by hot summers and cold winters. In January, the average minimum temperature is about 7° Fahrenheit; the average high is about 33°. In July, the average maximum temperature is 90°. On average, 13 summer days exceed 100°. Winds of 50 miles per hour can occur, most likely in the summer. Average annual precipitation is 16 inches, falling predominantly in May, June, and July. Thunderstorms are common, and are the main source of spring rainfall. Heavy rains can cause flash flooding along minor tributaries. Yearly snowfall averages 35 inches, and a few heavy snowstorms occur each year. Snow combined with heavy winds can create snowdrifts of several feet, making road maintenance and travel difficult.
An intermittent steam course runs south of Interstate 90, near Launch Control Facility Delta-01. This area also contains a few small pockets of wetlands. There are no known water resources at or near Launch Facility (Missile Silo) Delta-09.
Shrubs and trees are usually restricted to draws, gullies,and surface waters. Typical shrub species include silver buffaloberry, broomsnakemeed, greasewood, and some plum and chokecherry. Cottonwoods, willows, ash, and elms are common tree species growing along streams.
Amphibian and reptile species may include the Great Plains toad, painted turtle, garter snake, and western rattlesnake. United States Forest Service sensitive species (that is, species tending towards being a candidate for Federal listing as threatened) which are possibly found along Interstate 90 are tiger salamander, northern leopard frog, pale milk snake, northern earless lizard and northern prairie lizard.
Birds in the area include upland game birds such as pheasant, grouse and turkey. In addition, there are several raptor and hawk species including turkey vultures, eagles, red-tailed hawks, kestrels, ferruginous hawks, Swainson's hawks, prairie falcons, and occasionally peregrine falcons.
Wetland and riparian habitat along the Interstate 90 corridor support shorebirds, waterfowl, and other birds. Species that may be found in some of these habitats include redwing blackbirds, yellow-headed blackbirds, common yellowthroats, snipes, spotted sandpipers, and American avocet. Long-billed curlews may be present. Species that may be seen near marshes include short-eared owls and the northern harrier. Wetlands support a wide variety of migratory waterfowl. Species that may visit these wetlands include coots, Canada geese, herons, whooping cranes, pelicans, and numerous species of ducks.
Last updated: January 29, 2018