Spring floods on the Red River are now expected to approach the volume of floods in 2009, the highest since the 1997 flood of the century, according to provincial forecasters.
Provincial hydrologist Fisaha Unduce predicts that the Red River will reach the ridge around May 10 at a level just below that of the 2009 flood, which closed Highway 75 for weeks and required the evacuation of some rural properties.
Under favorable conditions, the crest of this spring will be somewhere between the floods of 2011 and 2009. In the worst case scenario, the flood could be even greater than in 2009.
In all three scenarios, the volume of water in this year’s flood is expected to exceed that of the 2009 flood, but water levels will not be as high because the river’s ice in 2009 raised water levels, Unduce said.
This year’s peak levels are not expected to be so high because all the ice has shifted from the river, especially in Winnipeg, which is protected from the Red River flood, he said.
However, a flood of 2009 will be a significant event that is likely to close most of Highway 75 in a few weeks and will require the precautionary evacuation of several dozen properties that could lose road access to emergency services. aid, said Manitoba Infrastructure Minister Doyle Pivnyuk.
Manitoba could be forced to bypass U.S.-bound truck traffic to Highway 3 if North Dakota closes Interstate 29, he said.
As early as March, Unduche lowered its estimate of a significant flood this spring. Then came the unusual snow in April, followed by unusual rains.
Four heavy rains swept through the province in April, with forecasters watching another major system expected to hit the region this weekend. It is expected to bring another 30 to 80 millimeters of rain in southern Manitoba.
“The probability of getting this rain in April was like 87 years old,” Unduce said.
Pivnyuk blamed the Colorado lowlands for bringing so much moisture to Manitoba.
“If it’s an Alberta trimmer, there’s not much moisture in that snow, and we have a lot of Alberta trimmers in the winter. But when we have low levels in Colorado, that’s variable,” he said.
“We get a lot of moisture there, and that’s where it connects to the Gulf Stream.”
Each community along the Red River has built flood protection infrastructure to cope with the expected peak in May.
Every city and community of the first nation along the Red in Manitoba is protected by a ring dike designed two feet above the 1997 flood level.
Any property outside these communities that was eventually damaged by the 1997 floods also had to build its foundation.
As a result, only a handful of farms and areas that can be cut are facing possible evacuations, Pivnyuk said.
The province is planning these evacuations by pre-registering people in the flood zone who may be affected, said Johanna Botta, deputy minister in charge of emergency management.
COMPARE The degree of significant flooding over the years:
Southern Manitoba Flood Coverage of 1826, 1852, 1950, 1979, 1997, 2009 and 2011 (Charlie Brockman / CBC News Graphics)
Sand packing machines have been delivered to communities in the Red River Valley and infrastructure officials are monitoring the floods by land, he said.
“Overall, our emergency response system has strengthened and we are in a good position to respond to events that may come our way,” Botha said.
The city of Winnipeg is also expected to notify additional properties of the potential need to build sand dunes.
Unduche said that with the flood in action, he did not expect the Red River to bend higher in Winnipeg by about 20 feet above the normal winter ice level on James Avenue.
As of Friday, the Red in Winnipeg was 17.3 feet from James. The river peaked at 22.6 feet James in 2009, mainly due to ice jams at a time when the flood could not be exploited.
The peak volume of the Red River at the watershed south of Winnipeg during the 2009 floods was 97,000 cubic feet per second.
Unduche said Red is expected to reach the ridge south of Winnipeg with a peak volume this spring somewhere between 94,000 and 121,000 cubic feet per second.
The flood of the century in 1997 reached 138,000 cubic feet per second.
The latest flood forecast in Manitoba
Spring floods on the Red River are now expected to approach the volume of floods in 2009, the highest since the 1997 flood of the century, according to provincial forecasters. 2:14
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