The Columbia Plateau is a “Flood Basalt” province in the Pacific Northwest of the USA. Geographically, it is a vast, relatively level upland created by successive layers of cooling lava, some reaching thousands of feet in thickness. Unlike the jagged Rockies nearby, this plateau features wide, sweeping plains and deep canyons where rivers (like the Columbia and Snake) have cut through the basalt layers. This region is a prime example of “constructive” volcanic geography, where internal forces added massive amounts of new rock to the continental surface, creating fertile volcanic soil that supports major agriculture today.