This regional view shows the striking visual effect of the valley-and-ridge topography of the Appalachian Mountains as viewed from the International Space Station. The image shows more than 500 km (300 mi) of this low mountain chain from northeast Pennsylvania (top right) to southern West Virginia, where a dusting of snow covers a patch of land (lower left).
Sunglint reflections reveal details of the Chesapeake Bay and the great bend of the Potomac River. Cities are difficult to detect from space during daylight hours, so the sickle-shaped bend of the river is a good visual guide for astronauts trying to photograph the nation's capital, Washington D.C. The farm-dominated Piedmont Plateau is the light-toned area between the mountains and the bay.
The Appalachian Mountains appear striped because the ridges are forested, providing a dense and dark canopy cover, while the valleys are farmed with crops that generally appear as lighter-toned areas. (Farmland is even lighter than usual in this image because the fields are fallow after the harvest.) Photo courtesy of NASA.