In the early morning hours of December 22, 2008, the earthen wall of a containment pond at Tennessee’s Kingston Fossil Plant gave way. The breach released 1.3 million cubic meters (1.7 million cubic yards) of fly ash—a coal-combustion waste product captured and stored in wet form. As fly ash dries, it is typically moved to new containment areas to continue drying, and it was one of these areas, housing dredge cells that facilitate further drying, where the containment wall broke. Some of the sludge traveled north through a valley, and some flowed to the east, where it damaged dozens of homes. The spill infiltrated the Emory River, buried some 120 hectares (300 acres) in sludge, and even knocked a nearby home completely off its foundation.  NASA Earth Observatory

Emory River before the coal ash spill Emory River, before the coal ash spill. Creative Commons photo by Chris   Emory River after the coal ash spill TVA temporary dike / weir being contructed in the Emory River arm (embayment) of Lower Watts Bar Reservoir. Credit: Steven Alexander / USFWS

The Thematic Mapper on NASA’s Landsat 5 satellite captured these images of the Kingston Fossil Plant and its surroundings on November 20, 2008, a month before the spill (bottom), and December 22, 2008, immediately after the spill (top). In these false-color images, water appears blue, and sediment-laden water appears light blue. Vegetation appears green, and bare ground and urbanized areas appear pinkish-brown. In the November image, walls visibly contain two adjacent slurry ponds at the plant—one in the northwest and one in the southeast—but in the December image, the walls of the northwestern slurry pond have given way. In this image, light blue slurry covers the ground to the north and east of the plant. Sediment also clogs the nearby Emory River, evident from the waterway’s relatively light blue color. NASA Earth Observatory

20 November 2008 Coal Ash Spill, Tennessee, acquired November 20, 2008. NASA Earth Observatory   22 December 2008 Coal Ash Spill, Tennessee, acquired December 22, 2008. NASA Earth Observatory    2008 Aerial image of Kingston ash slide pre-event 2008. TVA   23 December 2008 Aerial image of Kingston ash slide, 23 December 2008. TVA   8 October 2009 Aerial image of Kingston ash slide cleanup, 8 October 2008. TVA    Video of the spill aftermath