These badlands are located in Petrified Forest National Park, AZ. Summer thunderstorms and winter showmelt easily carve the soft shale and sandstone into a maze of sharp ridges; steep hillsides; and deep, V-shaped gullies. Water drains through the tunnels, or "pipes", inside the hills and gullies, washing out loose soil and undermining the slopes that later collapse as sinks and slumps. It takes about a decade for three inches of soil to wash away from a slope (Source: NPS sign at a nearby viewpoint). Imaged in December 2009.