Lake McConnell to have drained first into Lake Agassiz", an even larger lake to the southeast, "then into the Arctic Ocean via the Mackenzie River, then back into Lake Agassiz, and then back to the Arctic Ocean" at various times in its history. Either 8,300 or between 9,000 and 8,000 years ago, it divided to form Great Slave Lake and Lake Athabasca. These two and Great Bear Lake are considered its 'daughter' lakes. Lake McConnell Lake McConnell was a very large proglacial lake that existed in what is now Canada from 11,800 to 8,300 years ago. Other sources give starting and ending
Mackenzie River . Six other lakes in the watershed cover more than , including the Williston Lake reservoir, the second-largest artificial lake in North America, on the Peace River. The river discharges more than of water each year, accounting for roughly 11% of the total river flow into the Arctic Ocean. The river is frozen for most of the year, with the ice typically breaking up by early to mid-May in the south, and late May-early June in the north. Ice breaks up earlier on the tributaries, sometimes causing ice jams and flooding where they meet the Mackenzie. In the middle of