Mystery of the Megaflood

This movie was about a region in the state of Washington called the Scablands. A flood had carved out the majority of Montana, Washington, Oregon and Idaho. A geologist theorizes this mystery flood in the movie. He theorizes what he thought the cause of the huge gorges in these scablands that reach up to one hundred feet deep. There were many different theories for the scablands and how they were formed. It looked as if there had once been a river, but there was no proof of that being the case. It also looked as if it was an area under a glacier, but there was no proof of that either. It was in the 1920's that this geologist, Harlen Betz, theorized that there had been a huge flash flood that carved these gorges into this land. Scientists ignored his hypothesis because it was a mystery to them about where the water would have come from. It turned out Betz's hypothesis was proved to be correct. He proved that during the last ice age, there was an ice dam that was formed and held all of the water in a nearby lake. The ice dam ended up breaking, which sent all of the water rushing to this region in Washington, creating the scablands. This kept occurring over and over again which caused the gorges to be so deep.