Riverside communities west of Winnipeg could be in for a major crest of the Assiniboine River, the provincial government warned today.

Emergency Measures Minister Steve Ashton says the region near Portage La Prairie, Man., will see a "very significant crest" by midnight Tuesday.

Speaking to reporters Monday afternoon, Ashton said the next 48 to 72 hours will be critical along the Assiniboine River from Portage la Prairie to Winnipeg.

River levels in that area are expected to rise to one foot above levels from the 2011 flood, he said.

"We are, over that period of time, going to see a very significant crest. And I want to stress that the basic trend in the forecast has remained unchanged over the weekend," Ashton said.

He said the water coming from Saskatchewan has crested in Brandon, Man., without incident.

Brandon's dikes held as the river crested on Sunday. A smaller crest is expected July 17 or 18.

Winnipeg city officials say the Assiniboine is expected to crest there in the next three to four days, with river levels expected to rise by about a metre west of Route 90.

Officials said while basement flooding continues to be a risk, no Winnipeg properties are expected to require sandbags for flood protection.

'Incredible effort' by military

Ashton said the military has been part of an "incredible effort" to protect about 350 homes that could be threatened by flooding.

Some 150 of those homes could be flooded if the province decides to deliberately breach a dike at the Hoop and Holler Bend.

Flooding

The Assiniboine River has flooded a wide swath of land, including this area near Brandon. (CBC)

Ashton says that is a last resort but would be preferable to an uncontrolled breach which could cause millions of dollars in damage.

At least 742 people in Manitoba have been evacuated from their homes, many as a precaution.

"I don't want to underestimate the degree to which this is a huge challenge," Ashton said. "We are mobilizing every resource available to manage a challenging situation."

This summer flood was caused by torrential rain at the end of June and is expected to topple records set in 2011, which was one of Manitoba's worst floods.

As of Monday, 55 municipalities and communities have declared states of local emergency due to flooding, in addition to the provincewide state of emergency that was declared on Friday.

RM of Cartier residents told to raise dikes higher

Meanwhile, people living in an area just west of Winnipeg have been hit with news that their flood dikes are not high enough.

Firefighters are going door to door, telling residents in the Rural Municipality of Cartier they need to raise their dikes another two feet (0.6 metres) while others are being told they need to build them. 

Officials are preparing people for a flood crest of a foot higher than 2011 levels, but say they want people to build dikes to a level three feet (one metre) higher to leave room for possible wave impact.

Brandon-area flood

A property is surrounded by floodwater near Brandon as the crest hit on Saturday. (CBC)

Reeve Roland Rasmussen told CBC News that might not have been properly communicated.

"I always tried to be clear, the water level is going to be a foot higher. You have to allow for some freeboard," he said.

Rasmussen said the water is coming so quickly that provincial engineers are unable to survey people's properties to tell them how high to build the dikes.

"There was no time for that this year because a lot of the engineers are busy. Provincial engineers are just busy forecasting, working [and] our most important thing right now is that diversion ...what they're doing to try and increase capacity at the diversion will help everyone down here."

"Please use any stock piled sandbags you may have to reinforce your dikes. All attempts will be made to replenish your stock. Time is of the essence!" states an email sent by RM officials to residents.

The communities in the RM of Cartier include:

  • Dacotah​​
  • Elie
  • St. Eustache​
  • Springstein
  • White Plains

About 40 military members were in the region on Sunday. That number was to nearly double on Monday, to 75, as they help property owners get those dikes higher.

In the nearby RM of Saint François Xavier, the same race against the crest is on and there is a need for volunteers to help with around-the-clock sandbagging. 

Both the RMs of Cartier and St. François Xavier are looking for volunteers to help protect properties in the area.

Anyone who can lend a hand is asked to call the RM of Cartier at 204-353-4005 or the RM of St. François Xavier's emergency operations centre's public information line at 204-864-2874.

Relief in RM of Edward

There is some relief in the RM of Edward, which is located in the far southwest corner of Manitoba.

For about week, access in and out of the RM and the town of Pierson has been cut off due to overland flooding on roads and bridges.

Municipal Coun. Debbie McMechan says while that's still the case — and though the RM is still in a state of local emergency — the water level is coming down.

That has allowed officials to work on repairing bridges and roads.

As well, some of the 71 people displaced from their homes because of the flooding have returned to their homes.

"It's such a relief. Now it seems like there's different problems, but they aren't the problems of a really serious nature," McMechan said Monday.

She added that while roads and bridges are still covered in water, the province has said it will send a helicopter to the area to transport individuals out of the community in emergencies.

In Brandon, city councillors will meet on Monday evening to discuss asking the provincial government for disaster financial assistance.

If the assistance is approved, the city and affected residents would be able to apply for financial help to deal with flood-related damages.

With files from The Canadian Press