Apr 17, 2017

A glacial river has a dramatic change of course in Yukon's Kluane Park

Kaskawulsh Glacier, Yukon, Unorganized, YT Y0B
Canada
by
Brandie Weikle
,
CBC News
A view of the ice canyon that now carries meltwater from the Kaskawulsh glacier, seen here on the right, away from the Slims river and toward the Kaskawulsh river. Photo: Dan Shugar, University of Washington Tacoma
A view of the ice canyon that now carries meltwater from the Kaskawulsh glacier, seen here on the right, away from the Slims river and toward the Kaskawulsh river. Photo: Dan Shugar, University of Washington Tacoma

Climate change has caused the massive Kaskawulsh Glacier in the Yukon to retreat so much that its meltwater abruptly switched direction, in the first documented case of "river piracy" in modern times.

Instead of flowing into the Slims River and then north to the Bering Sea, the water has changed course and now flows south toward the Kaskawulsh River, the Gulf of Alaska and the Pacific Ocean, scientists have found.

Also known as stream capture, river piracy is a term used to describe a geologic phenomenon where a stream or river is diverted toward another body of water. It's usually caused by a dramatic tectonic event, such as a landslide or glacial dam collapse.

"This was the first event we could find where river piracy occurred right under our noses and due to contemporary climate change," said Dan Shugar, a geoscientist at the University of Washington Tacoma and lead author of a study published Monday in the journal Nature Geoscience.

Previous cases of river piracy may have taken place thousands of years ago or more, said Shugar in an interview with CBC News.