Rain, melting snow and ice jams forced waters in parts of Eastern Canada to rise Wednesday, submerging roads, filling basements and prompting hundreds to be evacuated from their homes as officials told people to prepare in case they had to seek higher ground.

From Atlantic Canada to Ontario, rivers overflowed and in some cases, water levels rose to heights some said they hadn't seen in years. Many roads were flooded and in New Brunswick, the RCMP urged people not to attempt driving through those areas.

"It's devastating," said Marc Thorne, mayor of the southern New Brunswick town of Sussex, where dozens of homes were flooded, including his own where has lived for 22 years.

"The Trout Creek has breached its banks at a height we haven't seen in many decades and a lot of subdivisions in town are impacted."

Meanwhile, the mayor of Perth-Andover called for a voluntary evacuation of his community of about 1,800 people, saying he feared that a rising St. John River could flood parts of the town.

Terry Ritchie said in a news release that residents are expected to find their own accommodations. The northern New Brunswick community experienced severe flooding in March 2012.

A message posted on the village website Wednesday evening said Hotel Dieu hospital had evacuated its patients as a precautionary measure and had temporarily closed the emergency room.

Premier David Alward was scheduled to go to Sussex on Thursday to meet with his public safety minister at Kingswood University, where some of those evacuated from their homes have taken shelter.

The neighbouring village of Sussex Corner declared a state of emergency as the floods made some roads impassable, but that was later rescinded as water levels receded.

Still, officials stressed that the flood situation was constantly changing and they told residents to remain alert.

"We can't predict what's going to happen," said Danny Soucy, New Brunswick's local government minister.

"That's why we keep telling people to make sure that they don't go near bodies of water, and if they live near bodies of water to watch what's happening and if anything changes they can get out fast and be secure."

In Quebec, outgoing premier Pauline Marois met with her successor, Philippe Couillard, on Wednesday for the first time since the provincial election and said the first topic she brought up with him was the flooding that has hit various parts of the province.

"I want to reassure all Quebecers that the outgoing government will work with the new government to make sure the transition does not complicate matters," she said after presiding over her last cabinet meeting.

"I would also like to tell Quebecers who are experiencing this unfortunate situation that I am thinking of them with all my heart, as is my government."

More than 600 people were forced from their homes in Sherbrooke, Que., as the Saint-Francois River swelled. Officials there said the river reached as high as 7.6 metres -- just short of the 7.9-metre record set in 1982 -- but more than four times its normal level of 1.8 metres as Sherbrooke Mayor Bernard Sevigny urged residents to be careful and patient.

Evacuations were ordered in multiple locations in the province. In St-Raymond, just west of Quebec City, about 300 people were forced from their homes, including four residences for seniors because of flooding of the Sainte-Anne River.

St-Raymond's downtown as well as the community's schools were closed until further notice. The same area was flooded twice in 2012, forcing 700 people from their homes.

Authorities in Quebec City said the water levels of several rivers reached crisis level and an emergency preparedness plan was activated.

High water levels also triggered states of emergency in Centre Hastings and Tweed in eastern Ontario, joining the nearby city of Belleville.

Richard Keeley, a spokesman for River Watch in New Brunswick, said a confluence of factors are contributing to the floods this spring in his province.

"Obviously this year, winter was longer than usual, there was a lot more snow than usual and it was colder than usual," Keeley told a news conference.

"Basically, the whole process has been slowed."

Officials in Manitoba warned Wednesday that the prolonged cold spring will make flooding more likely for a few homes in Winnipeg. Emergency Measures Minister Steve Ashton said the amount of ice in the water is pushing levels of the Red River up in south Winnipeg.

"The ice on the Red River is, in many cases, three feet-plus thick still," Ashton said.

"I can testify, coming from northern Manitoba, that's probably the kind of thickness you would expect to see on our winter roads into remote, northern communities."

In the western New Brunswick town of Woodstock, an ice jam knocked out several power poles, taking with it the electrical system leading to municipal water wells, said Ken Harding, the town's chief administrative officer. As a result, a boil-water order was issued though a diesel pump was started to restore water supply.

But Harding said he expected it would be days before it would be safe for NB Power crews to restore power to the town's water supply equipment.

Roads were also closed in Cape Breton and Prince Edward Island as a result of washed out culverts and rising waters.