N.W.T. hydrologist explains why flooding is so severe in Hay River

The Hay River has spilled over its banks, and N.W.T. hydrologist Anna Coles says hydrometric gauges installed to measure water levels in the river and its tributaries are showing record high water levels.

"The provisional data are showing that we are seeing the highest water levels that those gauges have recorded," said Anna Coles, a hydrologist with the N.W.T. government. 

The data is described as "provisional" because it still has to be verified by the Water Survey of Canada. 

The gauges span the Hay River and its tributaries in Alberta. 

Some hydrological records, like at the N.W.T.-Alberta border, go back to 1986, while records from other gauges go back just a decade.

Coles said a few factors are at play — high snow levels at the end of spring and existing high water levels in the Hay River Basin.

Over the last three or four days, the region was hit with a "very large precipitation event" that coincided right with ice breakup. 

Coles said she doesn't know if this kind of heavy precipitation has ever come right at the breakup period before. 

Ice is the final factor. Ice was parked through the town of Hay River and upstream.

"That ice being jammed in the river channels means that high water … can't get through to the Great Slave Lake and it's just all backing up," said Coles.

As Northern Alberta too faces high water events, Coles said the Chinchaga and Steen Rivers have records from the past 10 years.

"They are showing provisionally, again, high water levels," she said. 

Asked about high water in the N.W.T. in recent years, Coles said all the major basins to Great Slave Lake have had high rain since 2020. 

Coles said hydrologists continue to monitor hydrometric gauges along the Mackenzie River, where water level gauges are starting to rise, which is normal for this time of year. 

"We're just going to keep looking at that and watching how the ice breaks up over the next few weeks."

The network of gauges across the N.W.T. are operated by the territorial and federal governments.

Some of them have cameras mounted on them, allowing for real time observation of breakup at a specific location. 

Photos welcome

Coles said they also rely on real-time reports from river waters as the breakup unfolds and that anyone who wishes to share images or video of the breakup are "really useful sources of information for us."

Coles said the flooding this year has been "devastating to watch."

"Our thoughts are with those in Hay River being impacted by these floods ... We're hoping for a swift recovery of those flood levels."

Coles said people on the ground are "really the ones that can see how serious and how devastating" the flood is.

"We're watching the drone footage and the videos and the imagery that are coming from those folks in the town and along the river," she said. 

She said anyone can email their images to nwtwaters@gov.nt.ca