The Alsek River is a wilderness river flowing from Yukon into Northern British Columbia and into Alaska.The surrounding area from the Western edge of the Alsek to East of the East Alsek is known to locals as Dry Bay.
It starts at the confluence of the Dezadeash and Kaskawulsh rivers in Kluane National Park and Reserve. After flowing south into the northwestern tip of British Columbia, it is joined by the Tatshenshini River in Tatshenshini-Alsek Park. It reaches the Pacific Ocean at Dry Bay, in the Gulf of Alaska, south of Yakutat, Alaska, close to the northern end of the Alaska Panhandle. Although the river is navigable by kayak or rubber raft in its northern reaches, it rapidly becomes unnavigable—for any but the most experienced and skilled kayakers—at Turnback Canyon.
On older maps, the Alsek river is labeled as the Tatshenshini and vice versa. Some Yukon First Nation elders also refer to the river as the Tatshenshini.
The river flows next to the Lowell glacier which has sometimes blocked off the river and created a large lake behind it, “Neoglacial Lake Alsek.” The last such blockage took place in 1850; its release created a massive flood, washing away everything in its path on the way to the Pacific.
The river carries a lot of silt from the Alsek lake/glacier, which contributes to the river’s low temperature.
The Alsek and nearby East Alsek rivers were at one time connected, and the old river bed can still be made out on some maps.
The Alsek glacier contacts the Grand Plateau glacier, which faces the shoreline. Also in the same general area are the Doame foothills and Doame River.