The spring flood in the Red River is now expected to approach the volume of the 2009 flood, which was the highest since the 1997 flood of the century, provincial forecasters say.
Provincial hydrologist Fisaha Unduche forecasts that the Red River will crest around May 10 at a level slightly lower than the 2009 flood, which closed Highway 75 for weeks and required the evacuation of some rural properties.
Under favorable conditions, this spring’s crest will be between the floods of 2011 and 2009. In the worst case, the flood could be even greater than that of 2009.
Under 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 ice on the river in 2009 raised water levels, he said. Unduche.
This year’s peak levels aren’t expected to be that high because all the ice has moved off the river, especially in Winnipeg, which is protected by the Red River Floodway, he said.
Nonetheless, a flood on the order of 2009 will be a major event likely to close most of the 75 freeway for several weeks and require the precautionary evacuation of several dozen properties that may lose road access to emergency services, he said. Manitoba Infrastructure Minister Doyle Piwniuk.
Manitoba may be forced to divert US-bound truck traffic to Highway 3 if North Dakota closes Interstate 29, he said.
As recently as March, Unduche had downgraded the prospect of significant flooding this spring. Unusual snowfall followed in April followed by unusual rain.
Four major precipitation systems moved through the province in April and forecasters are monitoring another major system that is expected to hit the region this weekend. It is expected to bring another 30 to 80 millimeters of rain to southern Manitoba.
“The chance of it raining in April was like one in 87 years,” Unduche said.
Piwniuk blamed cooler temperatures in Colorado for bringing so much moisture to Manitoba.
“If it’s an Alberta clipper, there’s not a lot of moisture in that snow, and we had a lot of Alberta clippers over the winter. But when we have the Colorado lows, that’s the variable,” he said.
“That’s where we get a lot of moisture and that’s where it relates to the Gulf Stream.”
Every community along the Red River has flood protection infrastructure built to handle the expected surge in May.
All First Nations villages and communities along the Red in Manitoba are protected by a circular levee designed two feet higher than the 1997 flood stage.
All properties outside of those communities that were damaged in the 1997 flood also had to raise their foundations.
As a result, only a handful of farms and acres that could be cut face possible evacuations, Piwniuk said.
The province is planning for those evacuations by pre-registering people in the flood zone who may be affected, said Johanu Botha, the deputy minister responsible for emergency management.
Sandbagging machines have been delivered to communities throughout the Red River Valley and infrastructure officials are monitoring ground-based flooding, he said.
“Overall, our emergency response system has been augmented and we are well positioned to respond to events that may come our way,” Botha said.
The City of Winnipeg is also expected to notify other properties of the possible need to build sandbag levees.
Unduche said that with the floodway up and running, he doesn’t expect the Red River to crest higher in Winnipeg than about 20 feet above the normal winter ice level on James Avenue.
As of Friday, the Net in Winnipeg stood at 17.3 feet from James. The river peaked at 22.6 feet James in 2009, primarily due to ice jams at a time when the floodway could not be operated.
The peak volume of the Red River at the entrance to the floodway south of Winnipeg during the 2009 flood was 97,000 cubic feet per second.
Unduche said Red is expected to peak south of Winnipeg this spring at somewhere between 94,000 and 121,000 cubic feet per second.
The 1997 flood of the century peaked at 138,000 cubic feet per second.
Reference-www.cbc.ca