EXPERIENCING THE ICE AGE FLOODS; PART I

**Few geological events stagger the mind and defy the imagination as much as do the Ice Age Floods of the Pacific Northwest. To say they were large is inadequate by any standard. Words like enormous or gigantic or colossal grossly understate the reality. These several floods toward the end of America’s last ice age, some 15,000 to 20,000 years ago as geologists estimate, may be the most cataclysmic events ever to occur in the drainage of the Columbia River since the fiery formation of the earth’s surface itself. To start with, try to picture a “flash flood” roughly twice the height of the Washington Monument and fed by 500 cubic miles of undammed water.

**During the reoccurring advances of the Cordilleran Ice Sheet which pushed across western Canada and southward, one of the lobes of ice in western Montana repeatedly blocked a huge drainage thus forming and filling a massive lake. Periodically, and for reasons still not completely understood, this great dam of ice failed abruptly and released the impounded waters which immediately began to seek the sea 600 miles away and nearly 4,000 feet lower in elevation. This towering wall of water, at times nearly a thousand feet high and sometimes moving at nearly one hundred miles an hour, took only a few days to empty itself into the Pacific Ocean. As it raced out of Montana, across Idaho, through eastern Washington, and down what is now called the Columbia Gorge, it left chaos and destruction on a scale so wide and massive that it has taken over two hundred years to even recognize and confirm it. This would have been an astounding phenomenon had it happened only once, but in fact, it reoccurred multiple times, perhaps hundreds of times, and along its path the face of the earth was changed in many remarkable ways.

**Churning along with unbelievable power, the floodwaters scoured away surface lands and soils in eastern Washington down to (and into) the bedrock lava, created the channeled scablands, formed several immense temporary lakes, gouged out the gorge, and deposited vast quantities of rock, gravel, and sand not only along its path but also as far as sixty miles out to sea. For over half a century most leading scientists rejected and even ridiculed the theories and specific proofs one rebel geologist, J Harlan Bretz, began to place before them as simply being impossible. It took scores of years, a host of evidences, and some reluctant on-site investigation by many others to even begin confirming the scope and scale of the floods. To top off the list of incomprehensible characteristics of these mighty torrents, remember that each flood lasted but two or three days, perhaps, and in a week or so the waters which passed any given point had quickly reached the Pacific!

**Even today, although scores of individual scientific papers have been published, there are only a few books (and you can count the best of them on one hand!) for the common reader to use in grasping at the magnitude and proportion of what are now recognized as the most enormous single catastrophic events anywhere ever in North America. Some titles are Glacial Lake Missoula, Cataclysms on the Columbia, and Bretz’s Flood, but the best of all is On the Trail of the Ice Age Floods by Bruce Bjornstad, a Senior Research Scientist at the Pacific Northwest National Laboratories in Richland, Washington where my son David also works. As a geologist /hydrogeologist, Bruce has studied every aspect of the Ice Age Floods since 1980 and regularly publishes, lectures, and leads field trips concerning his favorite avocation.

**Soon I will be describing a flight which the three of us shared over some of the most dramatic features of the channeled scablands and coulees between Moses Lake and the Grand Coulee Dam on the Columbia River. David was our pilot; Bruce was our guide and mentor. I was the supercargo and had a marvelous time seeing and realizing the extent, size, and grandeur of these historic flood features. Stay tuned!