The south-central Manitoba town of Carman is dealing with its worst flood in over three decades, with hundreds of properties at risk, a bridge closed due to ice damage, and residents being warned to limit how much water they use.

As many as 300 properties in the town of about 3,000, located 75 kilometres southwest of Winnipeg, are at risk of flood damage, says Mayor Bob Mitchell.

"I've been living in Carman for 35 years and have not seen water back up like this," Mitchell said.

Carman officials declared a state of emergency over the weekend. About 30 to 40 homes have seen some water come into their basements and crawl spaces, Mitchell said.

The town's elementary and high schools were closed on Monday and will remain closed on Tuesday.

Ice jamming east of town on the Boyne River combined with overland flooding to threaten some homes in the community, the province said in a statement.​

While river levels went down on Monday, Mitchell said he's worried another crest could flow through town within the next two to 2½ days.

All the communities along the river are experiencing these ice jams, the same as we are," Mitchell said. "So when those ice jams give way and let the water come, they've all got to come through here."

Worst flood in decades threatens 300 properties in Carman, mayor says1:57

The ice jam "lifted" the bridge near Ryall Park in the centre of town on Sunday night, prompting officials to close the structure to traffic as they assess the damage.

As well, the town's water treatment plant is shut down following several water main breaks, Mitchell said. The town is temporarily getting its water from another source.

"We're facing a problem trying to keep up with water demand," he said. "We're trying to get people to limit, seriously limit the amount of water they use .… We're struggling."

Boyne River flooding in Carman

Ice jams have prevented the Boyne River and Carman Diversion from absorbing flood waters. (Kim Kaschor/CBC)

Last major flood in 1979

The deluge is the first major flood to hit Carman since 1979, when flooding caused $3 million in damage. The town, federal and provincial governments funded the $6-million construction of a diversion system in 1991 that has kept Carman flood-free until this spring.

The system is designed to divert Boyne River water west of Carman through a 10-kilometre-long channel to the northeast.

Boyne River, Carman spring flooding

Chunks of ice are breaking up in the Boyne River east of Carman. (Nelly Gonzalez/CBC)

Mitchell said the diversion itself has not failed. Rather, a warm winter and unusual spring melting conditions have led to ice jams east of town that kept water in the diversion from moving away from town.

"It has to do with the nice, beautiful winter we've had and everything. The water ran early, but it ran on top of the ice and under the ice, and the ice just collapsed," he said.

Mitchell said things have improved slightly — water levels went down about 70 centimetres overnight Sunday — but once the 6½-to-eight-kilometre-long ice jam outside town starts to move, levels could go up again.

"We're expecting another big surge of water from the west" once the ice jams give way, Mitchell said.

"Our biggest concern, of course, is the ice jams that are on the river downstream haven't gone away and that's what's going to cause us grief when we get the next flush of water from the west."

Carman mayor on flood situation1:00

'I didn't sleep,' says homeowner

Ken Snider and Kelly Rothwell, whose house is along the river, said they were able to save their home only after dozens of community members showed up to help them with sandbags on Sunday.

"People we didn't know, lots of young people — strong people — would walk by and and just pitch in, and the town crew has been incredible," said Rothwell.

Carman flood

Jeff Howie, a public works employee with the Town of Carman, directs traffic as crews dig up a broken water main down the street. (Kim Kaschor/CBC)

Snider said some water did seep into the house on Sunday night, but the damage was minimal because they have an old stone basement. Still, they have pumps working around the clock to push water out.

"I didn't sleep last night; I got up every 45 minutes to check the pumps," said Snider.

"Both pumps are working non-stop. That why we're so dependent on the pumps not to quit on us."

Mitchell is urging homeowners like Snider and Rothwell to keep their sandbags in place for the time being, due to the possibility of another crest this week.

Elsewhere in town, municipal crews pumped out a sewer line at the Boyne Lodge Personal Care Home all night Sunday to keep it from flowing back into the building, Mitchell said. About 80 senior citizens living with dementia and a range of other health issues live in the complex.

The Prairie Rose School Division, which operates Carman Elementary and Carman Collegiate, says the town has asked that both schools stay closed Tuesday "due to continued overland flooding challenges with R.M. of Dufferin rural roads and due to water supply challenges within the Town of Carman," superintendent Terry Osiowy said in a statement.

The Rural Municipality of Dufferin, which includes Carman, has also declared a local state of emergency due to flooding. Officials say they are watching water levels very closely and are bringing in water pumps for homeowners who need them.

Ice chunks float by as water levels remain high on Assiniboine River in Winnipeg0:28

With files from Nelly Gonzalez and Meaghan Ketcheson