How the Columbia River Gorge was carved — the Ice Age Missoula Floods that scoured it, and why Beacon Rock survived as a hard volcanic core.
Before we climb, look around at the whole shape of this place, because the gorge itself is one of the wonders of the world — a sea-level canyon cut clean through a mountain range, the only water-level route through the Cascades for hundreds of miles. And the way it got carved is almost beyond belief.
The Columbia had been cutting this canyon for millions of years. But the finishing blows came at the end of the last Ice Age, in a series of catastrophes we call the Missoula Floods. Far to the east, a wall of glacial ice kept damming up an enormous lake in Montana — and again and again, that ice dam failed. When it did, a wall of water hundreds of feet high came roaring down across the land at highway speed, carrying icebergs and boulders, and funneled straight through this gorge. It happened dozens of times. Those floods scoured this canyon down to the bones, ripped the soil off the walls, and left the sheer cliffs and hanging valleys you see today.
And Beacon Rock? It stood right in the path of all that water — and it held. Because it isn't ordinary rock. It's the hard, solid core of an old volcano, tougher than everything around it. The floods stripped away the soft cinder cone that once surrounded it and left the plug standing alone, a monument the water couldn't move. So when you look at that tower, you're looking at a survivor — the one thing here too stubborn for the greatest floods the world has ever known.
Photo: Mattsjc · CC BY-SA 4.0
