NOVA

Killer Floods

Passport Season 44 Episode 18 | 54m

All over the world, scientists are discovering traces of ancient floods on a scale that dwarfs even the most severe flood disasters of recent times. What triggered these cataclysmic floods, and could they strike again? In the Channeled Scablands of Washington State, the level prairie gives way to bizarre, gargantuan rock formations.

Aired: 10/17/17

Expires: 11/07/27

Rating: TV-PG

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