Setting the Stage

Long before Ice Age floods carved the coulees, waterfalls, and cliffs that dominate this landscape, vents from deep in the earth’s crust erupted again and again, supplying huge quantities of basalt that covered much of eastern Washington and parts of Oregon and Idaho in layers thousands of feet thick. Over time, tectonic forces pushed and pulled at the bedrock, opening deep fractures in the basalt. Millions of years later, Ice Age floods swept through this area, took advantage of these fractures, cut steep channels where the bedrock was weakest, created Palouse Falls and its canyon, and changed the course of the river. During the height of the floods, this entire area lay under hundreds of feet of water.

Washington · United States