On June 20, 2026, the Montreal region experienced an extreme rainfall event that reportedly brought between 100 and 170 mm of rain within a few hours. According to the application, runoff water overwhelmed local drainage infrastructure in the City of Dollard-des-Ormeaux, causing streets to flood and resulting in extensive damage to homes and vehicles. The proposed class action lawsuit consists of all owners and lessees of movable or immovable property in Dollard-des-Ormeaux that was damaged by the flooding. The application estimates that between 1,000 and 1,500 households across Montreal’s West Island were affected by the event.

The proposed class action alleges that the City of Dollard-des-Ormeaux and the City of Montreal negligently caused or exacerbated the flooding by failing to adequately prepare for, respond to, and mitigate foreseeable extreme rainfall events. The plaintiff alleges that the defendants failed to take precautionary measures before the storm, including increasing available stormwater storage capacity; installing or expanding adaptation infrastructure such as retention ponds, retention facilities, catch basins, and sponge parks designed to absorb, detain, and gradually release rainwater; implementing adequate flood-response measures during the event, including water diversion, pumping, and blockage removal; and upgrading and maintaining aging sewer and drainage systems.

The application further alleges that these failures occurred despite the defendants’ knowledge that climate change has increased the intensity and concentration of rainfall events. According to the claim, the defendants knew that Dollard-des-Ormeaux was vulnerable to flood risk because of its topography and had been aware that existing sewer and drainage infrastructure could not adequately withstand major rainfall events following the severe flooding associated with the remnants of Hurricane Debby on August 9, 2024. The plaintiff contends that the municipalities therefore had notice of foreseeable climate-related flood risks and failed to undertake appropriate adaptation measures.

The plaintiffs allege that class members suffered common injuries resulting from the flooding, including damage to residential property and personal belongings, reduced property values, increased insurance costs or loss of insurance coverage, temporary relocation and other out-of-pocket expenses, and physical and mental harms associated with flood-related contamination. The action seeks compensatory damages, punitive damages under the Quebec Charter, and injunctive relief requiring the defendants to undertake infrastructure improvements and other measures intended to prevent future flooding.


Wolofsky v. City of Dollard-des-Ormeaux and the City of Montreal

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Wolofsky v. City of Dollard-des-Ormeaux and the City of Montreal - application

Filed

Canada

Quebec

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Wolofsky v. City of Dollard-des-Ormeaux and the City of Montreal - application

Policy instrument

Risk

Just transition

Economic sector

Adaptation/resilience

Finance