Like the mega-landslide Chris visited, it’s hard to pick a photo to capture the scale of Earth history’s largest floods. This is a lovely side canyon off of Grand Coulee, carved by one or more of the floods that predate the opening of Grand Coulee itself. Even 90 years after J. Harlan Bretz started to tell the story of the floods, there’ still so much to be figured out about exactly how and when each feature of the landscape formed. Photo by A. Jefferson.