Montreal's South Shore was among the hardest hit by flash flooding on June 22, 2026, as intense rainfall overwhelmed drainage systems and caused widespread damage. The flooding, which began in the early morning hours, prompted emergency rescues and left many residents stranded in vehicles and homes.
Residents rescued as floodwaters rise
Emergency crews responded to numerous calls for help across the South Shore, including in the cities of Longueuil, Brossard, and Saint-Lambert. Firefighters used boats to rescue people from flooded streets and parking lots. One video showed a pregnant woman being rescued from a submerged car as neighbours helped each other during the crisis.
According to Environment Canada, the region received more than 100 millimetres of rain in less than six hours, equivalent to a month's worth of precipitation. The downpour caused rivers and streams to overflow, turning roads into rivers.
Wastewater systems overflow
The heavy rainfall also caused wastewater systems to overflow in several areas. Municipal officials reported that treatment plants could not handle the volume of water, leading to raw sewage being discharged into local waterways. Residents were advised to avoid contact with floodwater and to boil tap water before drinking.
“This is an unprecedented event for our community,” said Longueuil Mayor Catherine Fournier in a press conference. “Our infrastructure was not designed for this amount of rain in such a short period.”
Impact on transportation and homes
Major roads, including Highway 132 and Route 116, were closed due to flooding, causing traffic chaos during the morning commute. Public transit services were also disrupted, with bus routes diverted and commuter trains delayed. Several basements in residential areas were flooded, and some homes were evacuated as a precaution.
Hydro-Québec reported that thousands of customers lost power due to the storm, though service was restored to most within a few hours. The utility urged residents to stay away from downed power lines.
Government response and assistance
Quebec's Public Security Department activated its emergency operations centre and deployed teams to assess damage and coordinate relief efforts. The province announced that financial assistance would be available for affected homeowners and businesses through the General Disaster Assistance Program.
“We are working closely with local authorities to ensure that those impacted receive the support they need,” said Public Security Minister François Bonnardel. “Our priority is the safety of residents.”
Climate change concerns
Experts say that such extreme weather events are becoming more frequent due to climate change. “We are seeing more intense and frequent rainfall events, which overwhelm aging infrastructure,” said Dr. Marie-Ève Giroux, a climatologist at Université du Québec à Montréal. “Cities need to invest in green infrastructure and better drainage systems to adapt.”
Montreal Mayor Valérie Plante called for increased federal and provincial funding for climate resilience projects, noting that the city had already begun implementing measures such as rain gardens and permeable pavement.
Community resilience
Despite the devastation, stories of community solidarity emerged. Neighbours helped each other sandbag doorways, rescue pets, and share information about road closures. Social media groups were created to coordinate volunteer efforts and distribute supplies.
“We saw the best of our community today,” said Brossard resident Jean-Pierre Lefebvre. “People were out there helping strangers, offering shelter, and checking on the elderly.”
As cleanup begins, officials are warning that more rain is expected in the coming days, raising concerns about further flooding. Residents are urged to stay informed through local alerts and to avoid driving through floodwaters.
