A hoodoo is a tall, spindly structure that forms within sedimentary rock and protrudes from the bottom of an arid drainage basin or badland. Hoodoos form over millions of years of erosion in areas where a thick layer of soft rock is covered by a thin layer of hard rock. Over time, hoodoos form as a small cap of the hard layer protects a cone of softer rock underneath from erosion. Hoodoos can be a squat 5 feet (1.5 meters) tall or soar to 150 feet (45 m).
