CatIQ raises Montreal West Island flooding insured loss estimate to C$442m

CatIQ, Canada’s insured loss and exposure index provider, has raised its insurance industry loss estimate for the June 2026 flooding event that impacted Montreal’s West Island and the surrounding areas to CAD $442 million, a 7.5% increase from its second loss estimate of CAD $411 million that was issued in August.

On June 20th and 21st, a series of thunderstorms struck Montreal’s West Island, as well as areas south of the city, flooding hundreds of properties.

This marks CatIQ’s third insurance industry loss estimate from the event.

We covered CatIQ’s first loss estimate from the flooding event, where losses had reached CAD $409 million.

A second estimate was then released by CatIQ in August, where losses had risen slightly to CAD $411 million, before increasing to CAD $442 million in this September update, with growth primarily appearing in residential and commercial property lines

CatIQ confirmed that it will publish a fourth update of the market loss from the flooding event on December 22nd, 2026, six months following the event.

Caroline Floyd, Director at CatIQ, commented: “In many ways, pluvial flash flooding events were the story of the summer in terms of Canadian catastrophes, with several large population centres recording their wettest summer on record.

“Between June and August, CatIQ recorded six catastrophes dominated by pluvial flooding and sewer backup in Ontario and Quebec alone. These events resulted in more than 30,000 personal property claims. By comparison, between June and August 2025, we saw only one such event – albeit one that also directly impacted the Montreal metro area.”

Floyd added: “2024, thankfully, still stands as an outlier compared to both years, with major flash flooding in southern Ontario and the remnants of Hurricane Debby in southern Quebec generating nearly 100,000 personal property claims.”