Mystery of the Megaflood
Mystery of the Megaflood
In central Washington, on the opposite side of the Upper Grand Coulee from the Columbia River, and at the head of the Lower Grand Coulee, resides a three and a half mile crescent-shaped precipice known as Dry Falls.
Nearly twenty thousand years ago, as glaciers moved south, one ice sheet plugged the Clark Fork of the Columbia River, which kept water from being drained from Montana. Consequently, a significant portion of western Montana flooded, forming the gigantic Lake Missoula. Eventually, enough pressure accumulated on the ice dam that it gave way. It is generally accepted that this process of ice-damming of the Clark Fork, refilling of Lake Missoula and subsequent cataclysmic flooding happened dozens of times over the years of the last Ice Age.
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