Mars flooding seems about as likely as finding extraterrestrial life on the planet, but new evidence suggests the red planet really was subject to intense flooding during its lifetime.

NASA announced today the results of a study conducted by its Mars Reconnaissance Orbiter satellite. The study sought to recreate “ancient water channels below the Martian surface” in full 3D. Mapping out these channels helped scientists realize that Mars was home to massive floods in the last 500 million years.

The floods that created these channels are comparable to the floods that created the Channeled Scablands in Washington State during ancient times.

“Our findings show the scale of erosion that created the channels previously was underestimated and the channel depth was at least twice that of previous approximations,” said Gareth Morgan, a geologist at the National Air and Space Museum’s Center for Earth and Planetary Studies in Washington and lead author on the paper. “This work demonstrates the importance of orbital sounding radar in understanding how water has shaped the surface of Mars.”

NASA found the flood channels in the Elysium Planitia, an area along the Martian equator. The existence of the flood channels were covered up when much of the area was subjected to intense and frequent volcanic activity. NASA says that there are other water channels on Mars’ surface that were covered up in a similar fashion.

[Image: JPL/NASA]