'River Piracy': How Climate Change Diverted the Flow of Glacial Slims River in Just a Few Months

A new study revealed that the retreat of the massive Kaskawulsh Glacier in northern Canada has triggered a geological event, known to take about thousands of years or more, to happen in just a few months.

The study, published in the journal Nature Geosciences, showed that the retreat of the Canadian glacier change the course of meltwater. This phenomenon is known as "river piracy".

"Geologists have seen river piracy, but nobody to our knowledge has documented it happening in our lifetimes," said Dan Shugar, a geoscientist at the University of Washington Tacoma and lead author of the study, in a press release. "People had looked at the geological record -- thousands or millions of years ago -- not the 21st century, where it's happening under our noses."

Using a mapping drone, the researchers created a detailed elevation model of the glacier tongue and headwater region. The researchers observed that the glacial retreat has carved a 100-foot canyon that lets meltwater flow from one lake into another glacial lake.

The researchers noted that the Slims River has flowed out to the Bering Sea for the last 300 years, while the smaller Kaskawulsh River flowed to the Gulf of Alaska. However, the glacial retreat caused the glacial lake that fed the Slims River to change its outlet.

"Almost like when you see champagne poured into glasses that are stacked in a pyramid," commented Shugar.

As it turns out, the new outlet of the lake feeding the Slims River is another lake. The second lake drains through the Kaskawulsh River, which is in a completely different direction than the Slims River.

The river piracy that occurred in Canada's Kaskawulsh Glacier is slowly changing the local landscape. The exposed riverbed of Slims River is making it possible for the Dall sheep from the Kluane National Park to make their way to unprotected territory.

Additionally, the Kluane Lake, which is fed by the Slims River, is slowly shrinking every year. The researchers expect the lake to become an isolated lake cut off from any outlet as its water levels continue to drop.