Researchers studying dust in dried up Yukon riverbed

The Slims River valley is like a wind tunnel in the summer. Now researchers are taking a close look at all the dust that's kicked up into the atmosphere.

The Slims River valley is notorious for summer dust storms

Yukon's Slims River Valley is notorious for the dust that is kicked up by high winds in summer. Researchers are now studying the composition of the dust. (Jill Bachelder)

The Slims River valley in Yukon is known for its large dust storms in the summer months. Researchers are now studying the dust particles to try and find out how they affect the northern atmosphere. 

The Slims River (called A'ay Chu in the Southern Tutchone language) used to flow from the Kaskawulsh Glacier. But two years ago, the river dried up when the glacier retreated and its melt water was diverted.

Now, the vast riverbed is a test area for studying dust.

University of Montreal chemistry student Jill Bachelder spent her summer last year, researching and collecting dust from the Slims River basin.
University of Montreal student Jill Bachelder spent last summer collecting dust from the river basin. (Jill Bachelder)

"I'm looking at the mineral dust, [measuring] the sizes, and I am determining the chemical composition, in order to better characterize the dust," she says.

She's working in collaboration with a geography professor, Dr. James King, modelling the dust emissions.

The researchers are using air samplers in the area to collect the dust. Bachelder says they measure the chemical composition of the dust particles.

Winds originating from the Gulf of Alaska flow around the mountains and glaciers in Kluane National Park, then have a clear path across the dried mud flats. That creates a natural wind tunnel, lifting up fine dust particles into the air. 

Bachelder says since the river has dried up, a lot more dust is being kicked up by the wind.

Slims River (A'ay Chu) just disappeared

Scientists call it "river piracy". In May 2016, the Kaskawulsh retreated and its melt water was diverted into the Alsek River which flows into the Pacific Ocean, instead of to the Bering Sea.

James King, who's been working with Bachelder, says one question he is often asked about by people who live in the area is what the dried riverbed will look like in the future.

Dust is being collected with filter samplers placed in various locations in the Slims River Valley. (James King)

He expects vegetation to grow there, eventually — something that will cut down on the dust storms.

"In the past, in sub-tropical regions where you do have a change in the water source which is usually from people taking ground water — which happens in sub tropical regions — is that the fresh water from precipitation actually encourage vegetation growth," he said.

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