A melting glacier has caused the vast Slims River to disappear in just four days.
Ice melt from the Kaskawulsh glacier, one of Canada's largest, fed the Slims as well as the Kaskawulsh rivers. In the spring of 2016, the glacier began to recede. Because of this, meltwater from the glacier drastically changed its destination. Now, meltwater flows exclusively into the Kaskawulsh river and its dependent river systems. The Slims river, which once stretched as wide as 150 meters, has now disappeared.
The Kaskawulsh glacier retreated by 600 to 700 meters from 1956 to 2007. This suddenly accelerated in 2016.
A team of scientists monitored and documented the retreat of the glacier over the past years. An expedition to the area last year revealed a drastically different landscape to the scientists who had been studying the area for quite some time. According to the team's data, the river's disappearance began on May 26, 2016, and became complete on May 29.
“We had this project to study the river,” said James Best, a University of Illinois geologist and one of the team members. “So we went up there and the river was basically gone.”
“We found that all of the water that was coming out from the front of the glacier, rather than it being split between two rivers, it was going into just one,” Best added.
The team also found that the Alsek river, which feeds from the Kaskawulsh river, grew 60 to 70 times larger than the Slims river.
This is an example of river piracy, a phenomenon in which a river is diverted away from its own course and into that of a neighboring river.
Significant events like this can happen naturally as part of the Earth's geological processes. However, is the disappearance of the Slims River attributable to this?
The team thus analyzed climate models to see if this river piracy was likely to happen. They analyzed climate observations and the changes in the Kaskawulsh glacier beginning from the 19th century. Apparently, there was only a 0.5% chance that the glacier would retreat to the degree that it already has.
This data means that climate change and global warming caused the series of events that led to the disappearance of the Slims River.
Nowadays, Dall sheep from the nearby Kluane National Park are using what was once the Slims river's bed as a grazing ground. In this area, it's legal to hunt the sheep. The air in the area is also dusty now because strong winds pick up the dry river sediment. Fish are experiencing redistribution, and lake water chemistry has changed.
Though the area doesn't have many human inhabitants, the disappearance of the river can affect towns and ecosystems along the remaining bodies of water. Scientists also predict more instances of river piracy as glaciers around the world retreat due to climate change.
Though we all know that climate change can have severe impacts, we can't always predict the nature of these impacts and where they could possibly occur. The abrupt disappearance of the Slims river is a testament to how the world has become much more unpredictable due to climate change.
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