Abstract
The Lake Missoula flood was rejected by scientists for 40 years because it seemed too "Biblical" in scale. After geologists carefully examined the Channeled Scabland of eastern Washington, they finally accepted that glacial Lake Missoula existed and created a gigantic flood through eastern Washington, the Columbia Gorge and the Willamette Valley of Oregon. The evidence for this flood and the controversy surrounding it will be briefly discussed. Once the idea of a gigantic flood caught on, researchers, starting with Bretz himself, thought they saw evidence for many floods. In the 1980s Richard Waitt postulated 40 floods based primarily on rhythmites from Burlingame Canyon in the Walla Walla Valley. It was the existence of a band of volcanic ash in these rhythmites that especially convinced Waitt. He was followed soon by Brian Atwater who claimed there were 89 or more floods from the Sanpoil River Valley, northeast of Grand Coulee Dam. This adds up to over 3000 years of periodic flooding near and after the peak of the last ice age. Starting in the 1990s, the number of floods has been scaled back by some researchers. John Shaw and colleagues have published evidence for only one Lake Missoula flood, coming full circle back to Bretz’s original idea. The evidence for one gigantic flood is compelling and will be presented. An alternative hypothesis for the deposition of the volcanic ash band during one flood will be developed. The Lake Missoula flood can be used as an imperfect analog for the Genesis Flood, especially for the formation of water and wind gaps.