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Arts & Culture

NOVA: Killer Floods

Dettifoss Waterfalls, Iceland.
Courtesy of Blink Films
Dettifoss Waterfalls, Iceland.

Airs Wednesday, April 22, 2020 at 10 p.m. & Sunday, April 26 at 2 p.m. on KPBS TV + Thursday, April 23 at Noon & Sunday, April 26 at 9 p.m. on KPBS 2 + PBS Video App

Scientists Uncover Geologic Fingerprints Of Colossal Floods That Ripped Through Ancient Landscapes

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?

Over a vast expanse of Washington State called the Channeled Scablands, the level prairie gives way to bizarre, gargantuan rock formations: house-sized boulders seemingly dropped from the sky; a cliff carved by a waterfall twice the height of Niagara; and potholes resembling ones scoured out by rivers today, but ten times bigger.

Scablands, Wash., USA.
Courtesy of Blink Films
Scablands, Wash., USA.

Like forensic detectives at a crime scene, geologists study these strange features and reconstruct catastrophic Ice Age floods more powerful than all the world’s top ten rivers combined.

Dr. James Lawrence is a Senior Lecturer in Engineering Geology and Geotechnics at Imperial College London. In this photo he is seen abseiling the White Cliffs of Dover, UK.
Courtesy of Blink Films
Dr. James Lawrence is a Senior Lecturer in Engineering Geology and Geotechnics at Imperial College London. In this photo he is seen abseiling the White Cliffs of Dover, UK.

NOVA follows their efforts to uncover the geologic fingerprints of other colossal megafloods in Iceland and — improbably — on the seabed of the English Channel, where hundreds of thousands of years ago, another deluge smashed through a land bridge connecting Britain and France and turned Britain into an island for the first time.

These great disasters ripped through terrain and transformed continents in a matter of hours—and similar forces reawakened by climate change are posing an active threat to mountain communities throughout the world today.

Dettifoss Waterfalls, Iceland.
Courtesy of Blink Films
Dettifoss Waterfalls, Iceland.

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Glacial Lake Missoula, Missoula, Mont., USA.
Courtesy of Blink Films
Glacial Lake Missoula, Missoula, Mont., USA.

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