Researchers studying dust in dried up Yukon riverbed

The Slims River valley in Yukon is known for its large dust storms in the summer months. Researchers are now studying thedust particles to try and find outhow theyaffectthe northernatmosphere.

The Slims River (called A'ay Chuin 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 riverbedis a test areafor studying dust.

University of Montrealchemistry student Jill Bachelder spenther summer last year,researching and collecting dust from the Slims River basin.

"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 flowaround the mountains and glaciers in Kluane National Park, then have a clear path across the dried mud flats. That createsa 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.

• Retreating Yukon glacier makes river disappear

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.

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.