A 15,000 Year Old Scar

In this photo one can see the long "benches" carved into the cliffs above the Columbia River about 15,000 years ago, when "Glacial Lake Missoula" burst through its ice dam. This view is looking south into Oregon, and the blackened cliffs in the foreground are the result of a brushfire this summer just east of The Dalles. 

"About 15,000 years ago, in the waning millennia of the Ice Age, a vast lake known as Glacial Lake Missoula suddenly burst through the ice dam that plugged it at one end. In the space of just 48 hours, geologists believe, the collapse sent 500 cubic miles of water [more water than Lake Erie and Lake Ontario combined] cascading across the Pacific Northwest" and out to the Pacific Ocean between Oregon and Washington. (Megafloods of the Ice Age: Nova/PBS: 09/20/05)