Risk of spring flooding recedes in Manitoba

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This article was published 13/04/2022 (890 days ago), so information in it may no longer be current.

The province has started ratcheting down its flood response after water levels receded and the risk of flooding dropped.

Manitoba Transportation and Infrastructure’s Hydrologic Forecast Centre announced it had discontinued use of the Portage Diversion Thursday and the Red River Floodway on Friday as flows on the Red River continue to decrease.

Although parts of the province received up to 50 cm of snow, and up to 15 cm more is expected by noon Friday, flooding is less of a risk because temperatures are expected to remain near freezing until April 21 in most locations, delaying the snow melt and runoff.

“We couldn’t have had a better scenario,” said Jay Doering, a civil engineering professor at the University of Manitoba whose expertise was called on by the province during 1997’s “Flood of the Century.”

“We got this incredibly gentle melt out of this very large snowpack,” an accumulation he said is among the five largest snowpacks on record; it had posed a real risk of moderate flooding.

“That really worked to our advantage,” he said of the slow melt. While Manitobans might grumble about below-seasonal temperatures for the first long weekend of spring, they should consider it a blessing in disguise.

“If it gets really warm, really quickly, that’s what leads to large floods,” said Doering.

“We know, looking back through history, that the largest floods have always come later in the year. It stays cold and then all of a sudden it gets warm and then you get this massive release of water,” he said, pointing to major floods that occurred when there was a very late spring thaw.

“At this point in time, I don’t see us receiving any sort of runoff that we can’t handle,” Doering said Thursday. He noted the Red River Floodway was expanded after 1997 and communities have built up flood protection, including the doubling of the number of ring dikes to 16 from eight.

“I think where it becomes a challenge now for Manitobans, is if water levels rise to a point where we have to close ring dikes,” he said.

The province said flood forecasters will continue to monitor precipitation and collect data about snowfall amounts.Aan updated river forecast will be released next week.

carol.sanders@freepress.mb.ca