During the last great Ice Age that ended some 15,000 years ago, the Pacific Northwest was repeatedly decimated by cataclysmic floods unlike anything of modern times. Giant ancient lakes such as Glacial Lake Missoula were created as lobes of the massive ice sheets blocked river valleys. These "ice dams" broke time and again over the millennia, sending walls of ice-laden water, miles wide and hundreds feet deep, racing over the land at speeds up to 80 mph – scouring a fantastic landscape and leaving a fascinating geologic record. Now geologist Bruce Bjornstad has written the most comprehensive guide book yet to the incredible landforms scoured out by the Ice Age floods in the Mid-Columbia Basin. His new book, On the Trail of the Ice Age Floods: A geological field guide to the Mid-Columbia Basin explores the origins, timing and frequency of the Ice Age floods and describes each of 19 geologic features they left behind. It is also an exciting field guide to features, trails and tours in the Mid-Columbia Basin where we may witness today the awesome power of the ancient floods. The guide includes:
• Explanations of landforms created by the floods, from hanging coulees and giant gravel bars to ice-rafted "erratics" such as boulders carried on huge ice bergs and deposited hundreds of miles from their places of origin.
• Detailed descriptions of 70 distinct flood-formed features scattered throughout the basin, with driving directions to observation points
• 30 off-road hiking and biking trails where adventurers can walk and ride amid the flood geology.
• 5 driving tours and 2 aerial tours for day trips to view the scope of the landscape carved by the great floods.
Illustrated with more than 200 maps, schematics, photos and illustrations, including 16 pages of color plates, On the Trail of the Ice Age Floods provides a clear, concise and easily useable guide to the remarkable geologic record of the great Ice Age floods.
