Link: Ice Age Floods Institute (IAFI)
ICE AGE FLOODS INTRO
During the most recent Ice Age (18,000 to 13,000 years ago), and probably in previous Ice Ages, cataclysmic floods inundated portions of the Pacific Northwest. These Ice Age Floods originated primarily from Glacial Lake Missoula, but also from Lake Bonneville and perhaps as sub-glacial outbursts from under the continental ice sheet.
When part of that Cordilleran Ice Sheet pushed into the Lake Pend Oreille area of the Idaho Panhandle, it created an ice dam over 40 miles wide and 3000 feet thick, that blocked the Clark Fork River drainage and impounded Glacial Lake Missoula. At its largest, the lake was more than 2,000 feet deep at the ice dam and held over 500 cubic miles of water—as much as Great Lakes Erie and Ontario combined.