The Great Missoula Floods
During the last ice age, huge floods flowed across the Northwest
© Moo Moo Savaloy
During the last ice age, part of the ice sheet covering what is now western Canada advanced far enough into Idaho to block a major waterway, now called the Clark Fork River. The ice dam backed up the river, creating a gigantic lake in (what is now) Montana. Every so often, the weight of all that water would burst through the dam, sending a wall of water flowing across the areas of Idaho, Washington, and even down into Oregon.
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BirdNote®
The Great Missoula Floods
Adapted from a script by Todd Peterson
This is BirdNote.
[Peaceful sound of pool]
Migrating waterfowl rest in a pool at the base of a dried-up waterfall that was once five times wider than Niagara Falls. [Calls of Northern Pintails and Gadwalls]
We’re in a landscape like no other in the world. Here in the Grand Coulee region of eastern Washington State, you’ll find 100-ton boulders scattered across the land, gorges a thousand feet deep, and enormous potholes.
During the last ice age, part of the ice sheet covering western Canada advanced far enough into Idaho to block a major waterway, now called the Clark Fork River. The ice dam backed up the river, creating a gigantic lake in Montana. Every so often, the weight of all that water would burst through the dam, sending a wall of water flowing across Idaho, Washington, and even down into Oregon. At some of the bottlenecks in the Columbia River Gorge, floodwaters piled up 1,000 feet high. Some rivers even flowed uphill.
But now on this quiet, sunny October day, it’s just us and the pintails and Gadwalls, bathing and preening in a pool created by some of the greatest floods the world has ever known.
[Calls of Northern Pintails and Gadwalls]
For BirdNote, I’m Ashley Ahearn.
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Producer: John Kessler
Managing Producer: Jason Saul
Editor: Ashley Ahearn
Associate Producer: Ellen Blackstone
Assistant Producer: Mark Bramhill
Narrator: Ashley Ahearn
Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Northern Pintail 43082 recorded by W.W.H. Gunn.
Calls of Gadwall from Stokes Field Guide to Bird Songs CD, Kevin Colver ed.
BirdNote’s theme was composed and played by Nancy Rumbel and John Kessler.
© 2019 BirdNote October 2014 / 2019
ID# scablands-plungepool-01-2012-10-18 scablands-plungepool-01b
* Thanks go to geologist Dr. Aram Derewetzky for providing the backstory about J. Harlan Bretz and Joseph Pardee.
In the early 1900s, Dr. J. Harlan Bretz suggested that the landscape had been created by flood waters, but no one knew where the water would have come from and his idea failed to gain traction. In 1942, Joseph T. Pardee provided evidence of a "glacial Lake Missoula," which resulted in a huge amount of water that sculpted the landscape, as described by Dr. Bretz.
http://www.glaciallakemissoula.org/story.html
http://geology.isu.edu/Digital_Geology_Idaho/Module13/mod13.htm
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