Montreal flooding after heavy rainfall renews questions about infrastructure

MONTREAL — Shirley Dahan watched as rainfall steadily accumulated on her street in the Montreal suburb of Dollard-des-Ormeaux, Que., on Saturday before it rushed into her home, leaving about 2.5 metres of water in the basement and garage.

She said her husband briefly became trapped in the garage while checking whether a drain was working properly. Their son managed to pry open the door stuck by rising water, injuring his back and shoulder in the process.

“It was a disaster,” Dahan said Monday.

She said the water receded after a few hours but left behind a mess.

Dahan’s house was one of roughly 30 on her street affected by flooding after torrential rains swept through Montreal’s West Island and parts of the South Shore over the weekend. The flooding has renewed questions about how cities can prepare for increasingly intense rainfall events and whether existing infrastructure is equipped to handle them.

In Montreal, Quebec Premier Christine Fréchette said Monday during a press conference that governments will need to focus on adapting to a future in which extreme weather becomes more frequent. Resilience and adaptation will be key words going forward, she said.

Speaking Monday in the Montreal borough of Pierrefonds-Roxboro, one of the areas hardest hit by the weekend storm, Montreal Mayor Soraya Martinez Ferrada said the city will continue upgrading its sewer and drainage infrastructure.

However, she added that the volume of rain that fell over the weekend — up to 150 millimetres within a few hours — was so exceptional that even improved infrastructure would likely have struggled to handle it.

”We need to think about how the city itself can become a sponge,” said Martinez Ferrada.

She said the city is also looking at measures such as retention basins and other projects designed to absorb rainwater and reduce pressure on drainage systems.

While Martinez Ferrada was speaking about Montreal’s infrastructure network, some of the flooding also occurred in neighbouring areas, including Dollard-des-Ormeaux, which manages its own local infrastructure. The office of the Dollard-des-Ormeaux mayor did not immediately respond to an interview request.

Kathryn Bakos, managing director of finance and resilience at the Intact Centre on Climate Adaptation at the University of Waterloo, said municipalities across Canada will need a combination of infrastructure upgrades and nature-based solutions to adapt to increasingly severe rainfall events.

Among the most effective measures, she said, are updated flood-risk maps, larger stormwater retention systems and expanded green spaces capable of absorbing excess rainfall.

“We need more nature to act as more sponges,” Bakos said, echoing Soraya Martinez Ferrada’s comparison.

Wetlands, parks and other natural areas can slow runoff and reduce the amount of water entering overwhelmed drainage systems during heavy storms, she said.

Bakos said homeowners also have a role to play. They can install backflow prevention valves on their properties and improve drainage to move water away from foundations.

But she said the first step is making sure residents understand the flood risks to their homes and the mitigation strategies.

“The increasing trend of these extreme weather events is being driven by climate change,” she said.

Warmer temperatures allow the atmosphere to hold more moisture, resulting in heavier rainfall over shorter periods, she explained. “These are the kinds of storms that many communities used to expect once in a generation,” Bakos said. “Now we’re seeing them much more frequently.”

As flooding becomes more common, she said, an increasing number of homeowners are facing higher insurance premiums or reduced coverage in flood-prone areas.

In Quebec, Fréchette said the government provides financial assistance to some residents and businesses that are no longer insured for flood damage, with support of up to $385,000 for individuals and $485,000 for businesses.

This report by The Canadian Press was first published June 22, 2026.

Charlotte Glorieux, The Canadian Press