Geologists have known for some time that a giant flood occurred in the US Northwest when a glacial lake burst its banks. I wasn't aware that an even bigger flood happened in the middle of Canada caused by Glacial Lake Agassiz. Perhaps we'll get a Nature of Things documentary about it one of these days.
A flood of epic proportions drained at a rate of more than 800 Olympic swimming pools per second from a glacial lake that spanned the Prairie provinces more than 12,000 years ago, according to a University of Alberta-led study.
The finding bolsters a theory that the event may have propelled the warming Earth back into an ice age.
Geologists have long known of an ancient lake, Glacial Lake Agassiz, that occupied as many as 1.5 million square kilometers of what is now southern Manitoba and central Saskatchewan, up to the Alberta border. The lake formed as the three-kilometer-thick Laurentide Ice Shield atop the northern half of North America began to melt about 16,000 years ago, creating a dam that prevented would-be meltwaters from making their way to Hudson Bay.
Geomorphological evidence from northern Alberta also suggests that at some point that lake suddenly spilled out to the northwest along a major channel referred to as the Clearwater-Athabasca Spillway, through what is now Fort McMurray, Alta., into the Mackenzie River basin en route to the Arctic Ocean.
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