In the first modern case of “river piracy,” the 10-feet deep Slims River was left to dry due to the Kaskawulsh glacier melting in the direction to the Alsek River instead.

The Slims River runs from the Yukon down to the Bering Sea, while the Alsek River hits continental waters in the Pacific Ocean. It appears that the cause was a new 100-feet tall canyon that slowly took form as the glacier melt, causing the water to take a different route.

The Slims River. Image credit: Wikimedia.

The first case of river piracy

“River piracy” refers to the event where a river captures the flow of another. The “pirating” of the Slims River is the only modern example of this occurring, as these changes tend to take over 10,000 years to occur, researchers assure.

Researchers led by Daniel H. Shugar from Washington University relied mainly on drones to measure the elevation of the glacier and the rivers, determining that the drastic change in river flow had occurred in May 2016, leading the river waters to the Pacific Ocean.

Kaskawulsh Glacier
The Kaskawulsh glacier. Image credit: Frontrange Imaging

Without any doubt, they concluded that this particular event of river piracy was due to post-industrial climate change.

Changes in river flow tend to have a profound impact in how flora and fauna develop in the ecosystem at hand, as a plentiful and reliable source of water only ceases to be there. This is also expected to affect communities that use the Slims River for their purposes. Reported consequences include the reduction of water supplies and transportation methods for nearby vacation cabins, as announced by the Canadian Broadcasting Corp.

Observations began in 2013 when the Slims River was still classified as profound and fast-flowing. In fact, it was so fast that it was considered dangerous to step in its currents without proper equipment. Now, the Slims River was labeled by researchers as a “snake-shaped lake” instead of a river, as they were able to walk it through without getting most of their clothes wet. They believe that this incidence of river piracy has every indication of being permanent.

Skeptics may claim that the river went dry because of a dry season being in place, but this was disproved by the research team as the river’s waters came mostly from the Kaskawulsh glacier, a massive body of ice that’s over 9,650 square miles in size. Measurements indicate that the glacier has melt noticeably since 1899, as now it is at least 1.2 miles smaller than what it used to be.

According to The Washington Post, researchers say that there is only a 1 in 200 chance that both the glacier melting and the river piracy occurred by natural causes, without global warming being the origin. To confirm this, they employed computer models that simulated possible outcomes without greenhouse gasses and human-made atmospheric contamination being present. The results were transcendental and a possibly a solid piece of evidence that supports the thesis that climate change is altering the ecosystem in a significant manner in a noticeably short timeframe.

Source: Nature Geoscience