You are standing in the pathway of some of the largest floods ever known. They carved steep-walled canyons, sculpted immense waterfalls, and left behind landscapes found nowhere else on earth.
Massive Glacial Dams and LakesDuring the last Ice Age, a lobe of ice at least a half-mile high blocked the Clark Fork River in Idaho, creating an enormous lake called Glacial Lake Missoula. This ice dam failed - over and over - sending billions of tons of water rampaging across the land.
Raging Journey to the PacificThe thundering torrent of water, icebergs, and mud raced at speeds up to 60 mph, stripping away tons of soil and rock. The floodwaters raged across eastern Washington, through the Columbia River Gorge, and to the ocean.
How Many Floods Were There?No one knows for sure, but geologists discovered evidence the Lake Missoula and other glacial lakes filled and emptied many times during the last Ice Age.
(left illustration caption)At times, the ice dam was more than two miles wide and 30 miles long. Illustration by Stev H. Ominski
(center illustration caption)Pressure from rising water caused the ice dam to leak and crack. Over time, water began pouring from large fractures beneath the surface, eroding the dam from below until it suddenly
failed. Illustration by Stev H. Ominski
(right photo caption)You can visit many of the remarkable features created by the Ice Age floods, including Dry Falls, Steamboat Rock, and Beacon Rock. Photo by Lyn Topinka, English River Photography