Images from space solve mystery of water 'scars' on Earth's surface

Remains of ancient 'Ice Age floods', believed to have happened 10,000 to 20,000 years ago, have been discovered on Earth thanks to satellite images from space.

The floods, which devastated the US state of Washington, were found back in May by a Nasa and USGS (United States Geological Survey) observation satellite, called Landsat 8.

The satellite orbits Earth every 99 minutes and during one of its many trips captured photos of the Columbia Plateau in Washington, a rich agricultural area in the state where numerous crops, vegetables, fruit and milk are harvested.

What was unique about the photos is that they solved a long-standing mystery between geologists over rock formations in the area, known as Channeled Scablands, about 120km west of Spokane.

These rocks appear to form canyon walls and cliffs from ground level and break up the green and brown farmland that dominates the area. The source of water that formed them wasn't new at all and geologists now think that it came from the Cordilleran ice sheet, which formed a dam along the Clark Fork River during the last Ice Age.

The dam helped form a huge lake, in what is now Montana and is believed to have burst numerous times over thousands of years, resulting in 600 cubic miles of water cascading through the region on each occasion.

These floodwaters formed grooves, potholes, and long channels known as 'coulees' and would have flowed through the area at a speed 10 times stronger than all of the world's rivers, as per National Geographic.

Perhaps controversially this very suggestion for the origin of the 'scars' was made by a high school teacher named Harley Bretz, as reported by IFL Sciencebut was left as just that; a theory. In 1923, he theorised in a research paper that "The channeled scablands are the erosive record of large, high-gradient, glacier-born streams.

Lets hope that somewhere, Bretz feels vindicated.

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