As Glaciers Melt, Northern Rivers Increasingly Prone To Rapidly Change Course Or Even Disappear
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Shugar was a lead scientist who documented the first known case of river piracy in modern times in 2016 in Canada’s Yukon Territory. Then, Canada’s largest glacier melted so quickly it diverted a large river, and thus significantly reduced the water level of a lake it fed. For hundreds of years, the Slims River, or Ä’äy Chù, carried meltwater northwards from the vast Kaskawulsh glacier into the Kluane river then into the Yukon River towards the Bering Sea.
But in spring 2016, a period of intense melting of the glacier permanently redirected the meltwater of the Ä’äy Chù towards a steeper gradient east via the Kaskawulsh River, into the Gulf of Alaska thousands of miles from its original destination.
Now, scientists are turning their attention further downstream, to Alaska. A rapidly retreating glacier within Glacier Bay national park and reserve in Alaska is expected to change the course of a mighty river it feeds, the National Park Service geologist Michael Loso predicted in a paper published last month, and with it, demand adaptation from theecosystems and people who rely on the flow.
The Grand Plateau glacier in southern Alaska is about 350 metres thick at its tongue, and has long served as a barrier for the Alsek River. The waterway originates in the St Elias mountain range in Canada and flows south into Alaska, entering the Pacific Ocean in a channel that flows through Dry Bay, an area known for fishing and rafting. But over the next three decades, Loso and colleagues predict the Alsek will abandon its current channel at Dry Bay in favour of a steeper outlet 17 miles (28km) south-east, a pathway freed by the Grand Plateau glacier, which is thinning at a rate of up to 10metres each year.
EDIT
https://www.theguardian.com/environment/2021/may/03/receding-glaciers-causing-rivers-to-suddenly-disappear