Overview
- A near‑stationary storm system on Saturday dumped roughly 100–170 millimetres of rain in a few hours, producing rapid flash floods across Montreal’s West Island, parts of the South Shore and the Outaouais.
- Police and firefighters aided residents and cleared flooded streets while Transports Québec closed Highway 40 exits 52 and 55 and several borough buildings were shut for cleaning.
- Municipalities declared emergency measures: Saint‑Constant issued a local state of emergency and Saint‑Mathieu opened a shelter for displaced residents.
- Hydro‑Québec reported outages that peaked at about 18,000 customers Saturday evening and fell to roughly 4,400 by late morning Sunday, and Montréal–Trudeau airport operations that were disrupted Saturday largely resumed by Sunday.
- Officials warned the saturated ground raises flood risk for homes already hit multiple times, creating mounting recovery and insurance burdens for affected households and prolonged cleanup work for municipalities.