A National Natural Landmark, "the Drumheller Channels are the most spectacular example in the Columbia Plateau of basalt "butte-and-basin" channeled scablands. This is an erosional landscape characterized by hundreds of isolated, steep-sided hills surrounded by a braided network of (usually) dry stream channels. The landscape is the result of dramatic modification of the Columbia Plateau volcanic terrain by late Pleistocene catastrophic glacial outburst floods—the Missoula Floods. These floods occurred at a scale remaining unparalleled on earth, either in the geologic record or in historical account."