Few places on Earth are better prepared for floods than flat and often soggy Manitoba, where water from an area the size of Egypt winds up as it makes its way to Lake Winnipeg.
This province has entire towns surrounded by ring dikes, cities protected by flood channels and municipalities in possession of an arsenal of earth-moving, water-pumping and sandbag-filling machines.
Yet nothing prepared Manitoba for a flood season where multiple corners of the province took turns fighting and cleaning up after floods of a significant, if not historic, size.
In the south, the Red River is starting to recede from a flood that now ranks as the sixth-largest since the valley was settled by Europeans in 1812.
In the northern Interlake, Peguis First Nation was flooded out when the Fisher River flowed at its highest volume in 60 years.
To the west, communities on the east side of the Porcupine Hills and Duck Mountain endured unprecedented flash-flooding conditions as Colorado low stormwater poured down the Manitoba Escarpment. As a result, Dauphin Lake is now a foot over flood stage and still rising.
And in the east, the Winnipeg River is flowing in greater volumes than it ever has before, thanks to the worst flood on Lake of the Woods since 1950, the release of water from Lac Seul and heavy flows on rivers across northwestern Ontario.
“We’ve dealt with floods in the past, but what is different is it is coming from all angles and all directions,” Premier Heather Stefanson said at a news briefing earlier this week.
“It’s affecting many more Manitobans at the same time than maybe it has in the past.”
This year is different
While that’s not quite the case — there were 30,000 flood-zone evacuees from the Red River’s Flood of the Century in 1997 — the premier is correct in her assessment of the geographic scale of this year’s flooding, caused by a combination of heavy winter snow and unusual spring rains.
“What’s really been different about this flood year versus previous flood years is it’s not driven primarily from a single snowmelt or a single storm event like it was in 1997,” said Jay Doering, a University of Manitoba civil engineering professor.
“It’s been driven by consecutive back-to-back Colorado lows that have covered a large region of the province and have carried significant amounts of precipitation.”
While Doering is not a climatologist, he said he believes climate change has played a role in recent hydrological history. Most of the worst Manitoba floods over the past century have taken place over the past 25 years.
The recent extreme weather means Manitobans must reconsider what constitutes a one-in-100-year flood and redraw the lines around low-lying areas where homes and cottages and businesses shouldn’t go, he said.
“I think we’re going to have to have a look at what we’re using to drive our models to delineate a floodplain mapping,” Doering said.
“There really isn’t any other way to do this other than to basically undertake hydrologic and hydraulic modelling of the systems where this has occurred.”
This reckoning is unlikely to happen any time soon, as the province is still fighting flooding in eastern Manitoba. The Winnipeg River is still rising, albeit gradually, and is not expected to crest until June, the Lake of the Woods Control Board says.
According to Finance Minister Cameron Friesen’s office, Manitoba is too busy responding to floods to tally up the cost of this year’s floods. Preparing for the next ones will have to wait.
The Winnipeg River flood won’t be the end of the flood season. All that water heading into Manitoba has started to drive up the level of Lake Winnipeg.
Manitoba’s largest lake has risen two feet since the end of April and is now above the upper limit of its recommended operating range. Lake Winnipeg is expected to rise another foot by the second week of June to 716 feet above sea level, according to Manitoba Hydro.
Since the lake usually continues to rise into July, Lake Winnipeg will likely experience another summer when high winds from the north drive up wave action in the southern basin to the point where beaches get submerged and some shorelines wind up at risk of erosion.
‘Amazing turnaround’: Manitoba Hydro
The main beneficiary of the heavy flows into Lake Winnipeg is Manitoba Hydro, which suddenly finds itself with enough water to fully power its Nelson River hydroelectric plants.
Just this winter, widespread drought conditions left Hydro unable to meet its power-generation expectations.
“It’s quite an amazing turnaround when you look at where we were in September, October and November last year,” said Hydro communications director Scott Powell.
With the exception of the Winnipeg River and the big lakes, water levels elsewhere in Manitoba are dropping.
The province expects the Red River to remain high from the U.S. border to Winnipeg until late May, when it should start dropping rapidly. The river is expected to remain high within Winnipeg a little longer and start dropping quickly in early June, creating the possibility the Assiniboine Riverwalk will re-emerge sometime in early July.
This all depends, of course, on no more unusual rainstorms hitting Manitoba this spring.
The best-case scenario for the 2022 flood season is that the worst will be over by the time the Winnipeg River crests in June.
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