North

Breaking up isn't hard to do, especially when ice is low on the Mackenzie River

Low water levels and thin ice along the Mackenzie River and Great Slave Lake have contributed to early spring breakups.

Water levels are lower now than they were 'a decade ago,' says expert

River ice breaking up on Hay River in May 2018. This year's spring break up across the territory is happening earlier then usual, thanks in part to low water levels. (Kirsten Murphy/CBC )

Water levels in the Mackenzie River and Great Slave Lake continue to be low, which is one reason why spring breakup is happening earlier than usual.

"I wouldn't say it's any lower this year than it was last year but we can generally say that water levels today are lower than they were a decade ago," said Dustin Whalen, a scientist with Natural Resources Canada who monitors breakups in the Mackenzie Delta region.

"Based on what we're seeing from the breakup down south towards Yellowknife and Great Slave area and over in Alaska is that breakup has generally happened earlier this year than last year and in fact it's probably matching some of the earlier times we're seeing overall."

That's been the case in Hay River, which has had open water since April 21 — four days earlier than the previous record of April 25 set in 2011.

Water levels are brutally low right now.- Ross Potter

"Water levels are brutally low right now," said Ross Potter, the town's director of protective services. "There's rocks showing under the West Channel, it's really shallow now."

Potter said boats with props would have trouble navigating the river.

Similarly, the Yukon River broke April 23, tying the 2016 breakup day for the earliest in the past 100 years.

"It's all related to climate change through air temperature, sea ice conditions, snowpack, ground temperature," said Whalen. "The general trend we're seeing is breakup is generally earlier now than it has been even 20 years ago. If you look into the ocean we're seeing breakup almost 10 days earlier now than it was 20 years ago."

Whalen predicts Inuvik will experience breakup around May 14 or 15, about six days earlier than usual.

Warmer fall weather leads to ice forming later than usual, which means it isn't as thick or strong. Land-fast ice — the ice that collects on land — is also not as thick or wide as in previous years.

"So when the breakup finally meets the Arctic Ocean it won't have as much land-fast ice to deal with so we suspect that will be an earlier breakup right through into the ocean," Whalen said.

Lakes 'drying up'

It's not just the rivers and oceans that are experiencing changes. Lawrence Casaway is a 70-year-old hunter and trapper who grew up in the Taltson River area, and now lives near Detah.

"Inland lakes are drying up," he said. "From way back in the '60s to now if you compare it that way, you know there was a lot of water back in those years, now it's drying up, lots has to do with the dam."

Since 1968, the Bennett Dam along the Peace River in northern British Columbia has impacted water levels on Slave River, which is responsible for about 77 per cent of the inflows into Great Slave Lake. An N.W.T. Environment and Natural Resources website says flow changes along the Slave River have reduced the average high level of Great Slave Lake by 9 centimetres.

Casaway said melting permafrost is also causing abnormalities in the bush. He recounted coming across a six-inch hole in a bit of swamp which had a two-foot stream of water gushing out of it.

"Like where did that kind of thing come from, that kind of thing is happening, so I think the permafrost is melting."

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