​Across the country, thousands of Canadians are spending the weekend in a desperate struggle with rising floodwaters caused by unusually persistent rainfall.

In the hardest hit province of Quebec, Montreal Mayor Denis Coderre declared a state of emergency on Sunday afternoon. The order will remain in effect for at least 48 hours, giving the city the power to more effectively and quickly address the situation.

"If people's lives are in jeopardy, we need to think about the people first," he told reporters.

From CBC Montreal: Montreal declares state of emergency as floodwaters rise

The move comes after three dikes gave way in the city's Pierrefonds-Roxboro borough, located in the north end. Homes had already been evacuated in that neighbourhood, as well as on the two nearby islands, Île-Bizard and the smaller Île-Mercier.

Floodwaters in the province are expected to peak today due to continued rain in most of the affected areas.

Canadian forces have been deployed to help affected communities cope with rising water levels, including 80 soldiers in Gatineau, seen leaving their temporary headquarters here. (Ashley Burke/CBC)

In total, nearly 1,900 homes in 126 Quebec municipalities have been flooded, with more than 1,000 residents leaving the affected zones.

A total of 1,200 Canadian Forces personnel are expected to be deployed across western and central Quebec by the end of the day Sunday, as high water continues to threaten hundreds of residences. That's up from the 400 troops initially pledged.

'Remove the people'

A state of emergency was also declared Sunday in the community of Rigaud, Que., located just west of Montreal.

Mayor Hans Gruenwald Jr. has ordered a mandatory evacuation of the region's flood zones, saying authorities could no longer guarantee the safety of residents. He told reporters that firefighters will be going door to door to make sure people in the affected areas leave their homes.

"We will follow the fire department and actually remove the people if need be," Gruenwald said. "Because it is either that or services will be stuck to remove those people under a state of emergency at two o'clock in the morning on a stretcher. I'm sorry but we are not going to go there."

This is what Pierrefonds looks like from above as flooding continues to plague some parts of Quebec. Submitted by Daniel Meli. 0:54

Though the rainfall has started to die down, Environment Canada meteorologist Bruno Marquis said much of Quebec should still expect another five to 10 millimetres on Sunday.

In Gatineau, Que., near Ottawa, around 700 people have been forced out of about 390 homes as the Ottawa River continues to rise.

More than 80 soldiers arrived in the region Sunday morning to assist with the relief efforts. They've been tasked with filling and stacking sandbags, as well as rescuing families in homes cut off by water.

In the nearby village of Cumberland, Ont., just east of Ottawa, a heroic sandbagging effort failed to prevent dozens of homes from being flooded.

The eastern Ontario community of Clarence-Rockland has also been under a state of emergency since Thursday, with 181 buildings at risk of flooding.

An aerial view from a helicopter shows parts of Gatineau that are under water on Sunday. (Radio-Canada)

Alain Masson and his partner, Melanie Marcil, live in a waterfront home in Clarence-Rockland. But after a week of trying to keep the rising waters away from the property, they decided it was time to leave.

"It's beautiful when it's beautiful, but it's hell when it's hell. Hell is at its highest point right now," he told CBC Ottawa.

CBC's Amanda Pfeffer speaks with a resident of Gatineau, Que., who has been trying to protect his home from floodwaters since Monday 3:06

Electricity was cut off on one road where a house was floating away, tethered only by power lines, the town's mayor, Helen Collier, said Saturday.

Rob Kuhn, another Environment Canada meteorologist based in Toronto, said that eastern Ontario saw the most rainfall in the province. He added that upward of 80 mm of rain fell between Friday and Sunday morning in the Trenton area.

In southern Ontario, Lake Ontario's water levels are the highest they've been since 1993.

Toronto Mayor John Tory said city officials are monitoring the conditions on the Toronto Islands. Homes on Ward's Island are "potentially in jeopardy" if more rain falls, he said.

In Atlantic Canada, New Brunswick is the hardest hit, with 100 mm of rain falling in some areas in just two days — and Environment Canada warns there's more to come.

East Coast vs. West Coast

New Brunswickers are being told to stay away from rivers, streams and tributaries as the rain continues to fall across the province.

The province's Emergency Measures Organization says waterways are extremely dangerous as levels are high, fast and cold, and could be carrying debris.

They say the banks of waterways are also unstable and anyone who gets too close is at risk of being swept away. Residents are also being told to watch out for washed-out roads as the rain continues to fall across the province.

In British Columbia, rain combined with warm temperatures that have accelerated the melting of the snowpack have resulted in flooding and mudslides throughout the province.

Two people are missing in the province and dozens of homes have been evacuated.

States of emergency were called in Grand Forks, Kelowna, West Kelowna, Kootenay Boundary District and Fintry Delta.

A resident walks through the flooded streets of Île Mercier, in Montreal's west end. Mayor Denis Coderre declared a state of emergency on Sunday afternoon, which will remain in effect for at least 48 hours. (Ryan Remiorz/Canadian Press)

Dozens of properties north of Kelowna were also under an evacuation order due to flooding, while sections of the Trans-Canada Highway near Salmon Arm and Glacier National Park were closed due to mudslides.

B.C. Premier Christy Clark was in Cache Creek late Saturday morning to survey part of the damage.

RCMP say the search for a missing fire chief feared swept away by flood waters in Cache Creek, B.C., has now turned into a recovery mission, with Clayton Cassidy presumed dead.

In the Shuswap area east of Kamloops, a senior is missing after a home was swept away in a mudslide.

The missing man's family said the 76-year-old was last known to be inside the house that was swept up.

Simon Fraser University earth sciences professor Brent Ward says the recent warm temperatures appear to be causing some of the worst flooding the region has seen in more than a decade.