Approximately 15,000 years ago, a wall of water more than 150 meters or 500 feet in height raced across a section of central Washington state. As this flood quickly overflowed the natural boundaries of river channels, it began depositing house sized boulders on cliffs, and creating giant ripples in the landscape. In the span of only a few hours, thousands of towering and large hills were created in the landscape, as hundreds of feet thick of sediment were distributed over a vast area of the Ice Age era grasslands. This flood originated due to one of the largest glacial dam bursts in geologic history, which permanently changed the landscape over a wide swath of Idaho, Oregon, and Washington State.

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0:00 The Missoula Megaflood
0:47 A Vast Change in the Landscape
1:19 Geologic Setting
1:42 Lake Missoula
2:24 The Dam Breaks
4:00 Conclusion
Google Earth imagery used in this video: ©Google