scabland

Barren rocky plains of the West with little or no soil cover are called scablands. Biscuit scablands are mounded prairie lands with rocky, shallow clay soils. Bluebunch wheatgrass, parsnipflower, buckwheat, milkvetch, and other grasses may grow between the scabrock on deeper-soiled mounds. In “The Great Scablands Debate,” Stephen Jay Gould writes: “In the area between Spokane and the Snake and Columbia rivers to the south and west, many spectacular, elongate, subparallel channel ways are gouged through the loess and deeply into the hard basalt itself.” These channeled scablands were formed near the close of the Ice Age fourteen to sixteen thousand years ago when Lake Missoula, two thousand feet deep and covering three thousand square miles, repeatedly broke through its ice dam. The powerful waters of these floods—as many as a hundred of them over two thousand years—created massively deep channels in the Earth. Gould writes that such floods “could have moved 36-foot boulders.” The efforts of geomorphologists to discover the cause of these channeled scablands is an exciting story of controversy and brilliant detective work.

Pattiann Rogers