Chapter 13

Map of the Columbia Plateau

The Columbia Plateau

Although whole Oregon is not part of Columbia Plateau, it is very significant on physical geography of the state.The Columbia Plateau is  a basal flat region located between Rocky Mountains and Cascade mountains.The great Missoula Flood in Pleistocene time also shaped plateau uniformly covered with basaltic lava flows, but significant warping and faulting have caused elevations above sea level.Series of rolling hills, steep sided dry canyons,surficial lava flows are characteristics of Columbia plateau.

The plateau covers an area of about 100,000 square miles of southern Washington, Northeastern Oregon, and Western Idaho. Snake River and Columbia Rivers are major rivers irrigate the Columbia plateau. The climate is usually semiarid, and vegetation is limited mostly to shrubs and grasses.However,some parts of plateau is fertile and productive due to precipitation.

 Sources-The Geography of North America,2nd edition.Images by google.