The Columbia River Gorge is a striking natural landscape of mountains, bluffs, and cliffs that border the Columbia River as it passes through the Cascade Range. The Gorge has been a barrier and then an artery for the movement of people and goods, a zone of changing economic activity, and, most recently, a defined political entity requiring cooperation among the states of Oregon and Washington, the federal government, and four Native American tribes.Geology and GeographyThe Columbia River shaped the Gorge as a physical place by carving through successive uplifts and volcanic outflows beginning about three million years ago and reaching something like its basic form about a million years ago. Raging floods of glacial meltwater known as the Missoula Floods further shaped the landscape, repeatedly crashing through the Gorge between 19,000 and 15,000 years ago. They stripped away loose talus and soil to shape its present landforms, creating landslide hazards from undercut slopes on the Washington side and turning mountain streams into hanging waterfalls on the Oregon side.The Columbia River Gorge lies within six counties: Multnomah, Hood River, and Wasco in Oregon; and Clark, Skamania, and Klickitat in Washington. The western end of the Gorge is distinctly identifiable. To the southwest, the Sandy River marks a transition from high riverside bluffs to a much wider floodplain, rolling farmland, and the City of Troutdale. Across the Columbia, in Washington, high hills bend back from the river for the cities of Washougal and Camas.The Gorge makes a uniform impression east to Hood River, Oregon, and White Salmon and Bingen, Washington. From those points eastward, however, the visible landforms change, the result of the Missoula Floods stripping away soil to expose the underlying layers of basalt. Vegetation transitions from thick Douglas-fir forest to a sparser rain shadow regime of oak, cedar, and ponderosa pine. Because of that dramatic change in the landscape and climate, some accounts use Hood River as the eastern end of the Gorge. Others extend it another thirty-six miles to include the historic navigation barriers of the narrow and hazardous channel that French visitors called Les Grandes Dalles de la Columbia and Celilo Falls, both now submerged by twentieth-century dams, with the mouth of the Deschutes River as a convenient end point. The Columbia River Gorge National Scenic Area extends just east of the mouth of the Deschutes and Miller Island. MORE...