THE MISSOURI RIVER AS SEEN FROM SPACE

FROM:  NASA 

The Missouri River rises in the Rocky Mountains of western Montana, and flows generally to the southeast for 3,767 kilometers (2,341 miles) to its confluence with the Mississippi River north of St. Louis, Missouri. It is the longest river in North America. The river does not follow a straight southeasterly course along this distance, but includes many meander bends such as the one in this astronaut photograph from the International Space Station. This particular bend is occupied by Lake Sharpe, an approximately 130 kilometer (80 mile) long reservoir formed behind the Big Bend Dam on the Missouri River near Lower Brule, South Dakota. The lake surface is frozen and covered with snow, presenting a uniform white appearance. As meander bends develop, they tend to assume a distinctive U shape. Over time, the river channel can continue to cut into the ends of the “U,” eventually bringing them so close together that the river then cuts across the gap to achieve a shorter flow path and cut off the meander bend. When this happens and the meander ceases to be part of the active river channel, it may become an oxbow lake. The distance across the narrow neck of land (image lower right) associated with this meander is approximately 1 kilometer (0.62 miles). However, the river flow is controlled by the Big Bend Dam downstream, so the natural process of meander cutoff has been significantly slowed. Snow cover also highlights circular agricultural fields on the small peninsula within the meander bend.

This type of field indicates center-pivot irrigation, where water is distributed from a central point radially outwards using sprinklers to cover the field area. Crops grown here include corn and soybeans, according to data from the U.S. Department of Agriculture’s CropScape database. Astronaut photograph ISS038-E-23651 was acquired on Dec. 26, 2013, with a Nikon D3X digital camera using a 1000 millimeter lens, and is provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Center. The image was taken by the Expedition 38 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed. > View annotated image Image Credit:  NASA Caption-William L. Stefanov, Jacobs, NASA-JSC.

THE CENTENNIAL MOUNTAIN RANGE



Centennial Mountains

This 28,000-acre mountain range, which forms the boundary between southwest Montana and Idaho, is some of southwest Montana’s wildest country. It is considered an important corridor for wildlife movement, providing an east-west trending mountain range connecting the Yellowstone Ecosystem with the rest of the northern Rocky Mountains. Abundant wildlife in the Centennial Mountains include moose, elk, deer, wolverines, badgers, black bears, a wide variety of birds, and occasionally wolves and grizzly bears. Due to the presence of grizzly bears, proper food storage and carrying bear spray is encouraged. A variety of waterfowl, including trumpeter swans, can be found on the adjoining Red Rock Lakes National Wildlife Refuge. About 60 miles of the 3,100-mile Continental Divide National Scenic Trail ( CDT) runs through the mountain range. The CDT through the Centennials is usually well-maintained, although natural events can change conditions rapidly. Several side trails provide access from both the Montana and Idaho sides of the CDT. Wildflowers are especially abundant during the mid- to late summer. CDT travelers should be aware that guard dogs on the Sheep Experiment Station are very protective of the sheep herds and very aggressive toward domestic dogs (keep them leashed through Agricultural Research Service lands).

FROM: USA.GOV WEBSITE