Dry Falls consists of skeletal cliffs left from what was once the world’s largest waterfall, bearing witness to the catastrophic floods that swept over Eastern Washington at the end of the last Ice Age. The falls began 20 mi. to the south and receded upstream through powerful erosion, creating the canyon below, the lower Grand Coulee, as floodwaters hurled several cubic miles of rock over vast downstream areas. Today Dry Falls remains one of the most spectacular geologic wonders of the Age of Ice.