Today Hot Report

What unleashed a catastrophic flood that scarred the American Northwest? To find out the answer, watch “Mystery of the Megaflood” on NOVA, PBS. Check out local listings here. The program was originally broadcasted on September 20, 2005.

“Mystery of the Megaflood” features a dogged geologist sticking to his bold theory for decades despite virtual professional banishment. Eventually, other geologists joined his cause and filled in the intricate details, which NOVA recreates in stunning computer animation to show what may be one of the most spectacular series of events ever to occur on our planet.

The so-called “scablands” are a vast region of weird terrain 200 miles east of Seattle, including gorges hundreds of feet deep, enormous pits, huge boulders scattered as if dropped by giants, undulating hills that look like huge ripples, strange layers of silt and ash, and a “waterfall” five times wider than Niagara, but without any water (see Explore the Scablands). The name “scablands” perfectly suits the scarred and wounded landscape, which baffled most geologists throughout the 19th century and much of the 20th. To them, no plausible explanation fit all the facts.

As per Wiki, The “Scablands” were apparently created by the cataclysmic Missoula Floods that swept periodically across eastern Washington and down the Columbia River Plateau during the Pleistocene epoch. Geologist J Harlen Bretz coined the term in a series of papers in the 1920s. Debate over the origin of the Scablands raged for four decades and is one of the great debates in the history of earth science.

NOVA takes viewers on a virtual tour inside a glacier to see how tremendous pressure creates tunnels of supercooled water that, over time, fatally weaken the structure of an ice dam, causing it to fail. The current plot twist to the scablands story is that a deluge happened not once, but repeatedly, as ice dams reformed and the glacial lake refilled, only to empty again and again onto the scarred terrain of what is now eastern Washington.