Yellowknifer completes 800-km trip along Canada’s longest esker

Yellowknife resident Dwayne Wohlgemuth has completed an 800-kilometre hike along Canada’s longest esker, a trip selected by the Royal Canadian Geographic Society as its expedition of the year.

Eskers are ridges of sediment left behind by glacial rivers in the last ice age. The Exeter Lake esker is one of the largest in the world, running from the NWT-Nunavut border to the Acasta River, northwest of Wekweètì.

Wohlgemuth began the hike on July 28 and concluded the trip on September 3.

In a message posted using satellite technology from his finishing point, Wohlgemuth said the journey had involved 54 boat crossings. He counted 32 muskox, nine grizzly bears, six caribou, four wolves, four moose, and a fox during his 37-day quest.

He’s now paddling from the esker’s end to Behchokǫ̀ with his family. Together, the family made headlines last summer when they paddled for more than 100 days through the NWT’s barrenlands.

“It’s such a geological treasure here in the North,” Wohlgemuth said of the Exeter Lake esker before his departure in late July.

“Eskers are so important for wildlife and also for Aboriginal peoples, for hunting and travelling in the past.

“It’s a feature we have on the barrens in the Northwest Territories that I don’t think we quite appreciate as much as we should.”

‘Unique experience’

While the trip represented a personal test of endurance, Wohlgemuth’s plans were also of interest to a range of scientists for whom eskers are central to their work.

Paul Frame, a wolf biologist, has spent months tracking more than a dozen wolf dens and their inhabitants on the NWT’s eskers.

“How lucky is he to get to do that? It’s a pretty unique experience to hike along an esker,” said Frame by phone last month.

“Most of the wolf packs that we worked with had their den sites in eskers. We had evidence of wolves perching on an esker and observing [for prey] while using the wind to help escape from bugs. And then for travel, it’s much easier to walk on an esker than through a bunch of hummocks and wetland.”

A map of the esker hike prepared by Dwayne Wohlgemuth and Keith Robertson.

Wohlgemuth’s wolf sightings will be of interest to Frame, who fears that – despite programs to cull wolves in order to protect caribou numbers – the loss of caribou will mean NWT wolves die out, too.

“The wolves are dependent on the caribou. So if the caribou are gone, basically, unless there’s a big increase in muskox, the wolves will be gone too,” he said.

“In the barrens, we found that wolf population dynamics were driven by access to caribou. So if wolves don’t have caribou, then there’s nothing for them to live on.”

Can eskers help find diamonds?

Esker expert Don Cummings, at Carleton University, said Wohlgemuth’s hike will provide “a fantastic dataset” for scientists.

“It’s an amazing thing that Dwayne is doing,” Cummings said while Wohlgemuth was midway through the trek.

While researchers have some aerial images of the esker and have done some work on the ground, Cummings said Wohlgemuth was “getting in there with a scalpel and taking photos of the surface sediment that’s on the esker every hundred metres or so.”

He added: “By the end of this, we will have this very detailed understanding of the nature of the surficial sediment on the esker. Dwayne is really providing something that’s never been done before.”

That research has practical applications, Cummings said, not only for the field of environmental science but also for companies in mineral exploration.

At the moment, there are competing theories regarding how eskers form: one school of thought suggests eskers are deposited in one go and are long, consistent channels, while another argues they are dropped in short segments as the ice retreats.

Cummings said that matters because if an esker is one, long segment, and you find a kimberlite pipe containing diamonds in one part of it, that acts as a “regional dipstick for mineral exploration.” But if eskers are actually a series of short segments, the same won’t be true.

“If we can gain some insight into that, it will help companies improve their exploration models using eskers,” he said.