Ob-Irtysh River

The ob river originates in the Altai Mountains in southern Russia and flows northwest across the Western Siberian Lowland, a vast expanse of flat land surrounded by mountains on three sides and the Arctic Ocean to the north. The Irtysh River begins in the highlands of China's Sinkiang Province, flows to the northwest, and joins the Ob near the town of Khanty-Mansiysk well within the Western Siberian Lowland. To the east of the Ob/Irtysh Basin and along the foothills of the Central Siberian Highlands the Yenisey River flows north to its mouth on the Arctic Ocean. Both of these river systems move considerable volumes of water across the flat expanse of the confined lowland.

Because the rivers flow north, they freeze in the fall of the ...