The tranquil beauty of today’s Gorge belies the ~50 million years of volcanic and floods-induced mayhem that created this natural wonder. For well over 20 million years the Columbia River has slowly cut its valley through layers of basalt, taking many paths to the sea. By the time of the Ice Age Floods the Columbia River occupied a typical V-shaped river valley along its current path.

Beginning about 17,000 years ago, multiple cataclysmic Ice Age Floods, up to 1000 feet deep, rampaged down the valley, ripping basalt bedrock out of the valley walls and scouring the valley floor. Giant whirlpools plucked basalt bedrock from the bottom. Bedrock hoodoos, streamlined basalt buttes, hanging stream valleys, landslides, huge gravel deposits and the box-like cross section of today’s Gorge were left behind as the Floods subsided. Also left behind are ceberg-transported erratics that mark the upper limits of the Flood waters that backflowed up tributaries and backfilled adjacent basins. 

Though hardly recognizable in a human time scale, the mayhem continues to this day, with devastating fires, mud flows and landslides, eventual earthquakes and volcanic eruptions. It is not as serene as it appears!