Sand Hills of Nebraska

Nearly a quarter of Nebraska is covered by the Sand Hills, ancient sand dunes made of sediment eroded from the Rocky Mountains by the giant Pleistocene glaciers from 1.8 million to 10,000 years ago.

The sediments washed out onto the plains and today grassland vegetation prevents them from blowing or washing away. They span an area of about 37,000 square miles in western Nebraska, making them the largest sand dune formation in America. It is one of the least disturbed remnants of the vast prairies that once filled the central United States.

The sandy soils of the Sand Hills aren't like any other soils in the Great Plains. They were not attractive to farmers, so the area was left largely unplowed by European settlers, allowing unique grasses and plants to grow there. The area is an important habitat for migratory birds, such as the sandhill crane, one of only two species of crane native to North America.

This simulated natural-color image from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite shows a portion of the Sand Hills region, the landscape rippled by crowded yellow-tan and lavender-brown dunes. The area doesn't drain water very well, and so the hollows at the bases of dunes are filled with brilliantly blue lakes.

The effects of farming, however, are creeping into the region. It is easy to see that some of the emerald green vegetation is being cultivated, rather than growing naturally--perfect circles of vegetation resulting from center-pivot irrigation appear in the scene, as well as fields with sharp angles and straight lines.

This ASTER image covers an area of about 36 by 38 miles and is centered near 42.1 degrees North latitude, 102.2 degrees West longitude.

--Bjorn Carey

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Credit: NASA/GSFC/METI/ERSDAC/JAROS and U.S./Japan ASTER Team