Boats of the Mackenzie River watershed carrier business in 1947. The last steam-propelled sternwheelers, the "S.S. Distributor" and "S.S. Mackenzie" were retired around the same time. In later years, with the construction of the Mackenzie Highway from Alberta to Great Slave Lake, the importance of the Athabasca-Slave River route dwindled and NTCL operations were based from shipyards in Hay River after 1959. NTCL became the primary water operator in the Mackenzie River watershed with the purchase of Hudson's Bay Company's fleet and equipment in 1958, and the total buyout of Yellowknife Transportation Company in 1965 including its fleet of diesel tug boats. Other small commercial operators
Mackenzie River the northwest, establishing the present flow direction to the Arctic. Fluvial deposits and other erosional evidence indicate that around the end of the Pleistocene, about 13,000 years ago, the Mackenzie channel was scoured by one or more massive glacial lake outburst floods unleashed from Lake Agassiz, formed by melting ice west of the present-day Great Lakes. At its peak, Agassiz had a greater volume than all present-day freshwater lakes combined. This is believed to have disrupted currents in the Arctic Ocean and led to an abrupt 1,300-year-long cold temperature shift called the Younger Dryas. The Mackenzie carries a very large