The Kaskawulsh Glacier in the Yukon Territory retreated about a mile and the water from its snout reversed direction and began draining toward the Gulf of Alaska and Pacific Ocean rather than north toward the Yukon River, which flows into the Bering Sea. Until 2016, an ice dam channeled the glacial melt water through the Slims River and north through Kluane Lake. As the glacier receded, the flow shifted to the Kaskawulsh River then south to the Alsek River and into the Gulf of Alaska. Such “river piracy” as a result of a retreating glacier is rare, and is the first reported case in modern times.

Location map of the Kaskawulsh Glacier with the old and new meltwater flow directions indicated. Modified from Google Maps.
Satellite image of the glacier with old/new flow directions. Modified from Google Maps.
The ice canyon that now carries meltwater from the Kaskawulsh glacier (on the right) away from the Slims river and toward the Kaskawulsh River. (Photograph: Dan Shugar/University of Washington Tacoma)

More information is available on several media outlets, including University of Washington, CBC News, Phys Org, and USA Today.