The distinctive features that characterize the pitted landscape of the Channeled Scablands on the upper Columbia Plateau are believed to be the remnants of a series of catastrophic floods that surged across this area during the last Ice Age. Raging floodwaters cut through the channels that carried the Columbia River carving out deep canyons and sculpting hundreds of ship rocks. As the earth's climate moderated, the land as we see it today began to take form. The Columbia resumed its original course westward along the northern rim of the plateau to the North Cascades before heading south. Many of the floodways dried up, leaving behind dry canyons - coulees - with sheer walls of exposed layers of basalt. Some of the deeper basins continued to hold water and became lakes - such as Soap Lake, Moses Lake, and Potholes. To witness the dramatic effects of these cataclysmic events explore the Banks Lake area where, until recent times, the Grand Coulee was all but a vast dry wash, or travel up the smaller Moses Coulee. View Steamboat Rock and visit the Interpretive Center at Dry Falls, a 3 1/2-mile wide dry cataract that drops 400'.
Some of the Columbia's most spectacular scenery can be viewed by boat along a 30 mile stretch between Rock Island and Vantage. Eroded canyon walls display angular columns and crumbling towers. Motorists should visit the Ginkgo Petrified Forest and Interpretive Center where over 200 species of trees, including the Chinese ginkgo, once grew near the banks of the ancient river. Entombed by primeval lava flows and preserved by unique chemical reactions, these "trees of stone" were gradually unveiled as the land uplifted and the Ice Age floodwaters wore away their basalt shrouds.
