Insured losses from the severe thunderstorms that hit southern Ontario and southern Quebec from June 30 to July 3 have risen to $491 million, according to the latest estimate from Catastrophe Indices and Quantification Inc. (CatIQ).
The 90-day figure is up from $439 million at 45 days and from CatIQ's initial estimate of $374 million. It covers commercial and residential property, auto claims and additional loss adjustment expenses.
Most of the latest increase came from the residential line. That's a shift from the 45-day update, when CatIQ said growth mainly came from commercial lines.
CatIQ's high-resolution data shows how concentrated the losses were. More than 45% of the incurred personal lines loss came from just two forward sortation areas (FSAs), the postal code districts insurers use to aggregate claims, in Nepean.
Caroline Floyd, CatIQ's director, said Ottawa had its wettest summer on record in 2026 and that this event was a primary contributor. Of the nearly 550 mm of rain that fell on the city from June to August, nearly 120 mm fell on Canada Day alone.
"All told, more than 70% of the incurred total and more than 60% of claims for personal property arose from Nepean and communities on the southwest side of Ottawa," Floyd said.
Local officials had reported more than 4,500 basement floods after the storm, including sewer backups and drainage failures, as Insurance Business reported in September.
CatIQ's next update on the event is due on January 5, 2027.
CatIQ also lowered its estimate for the Bald Range Fire, which affected Summerland, British Columbia, and the surrounding area in August. The 45-day figure is $293 million, down from an initial $313 million. That puts the event below the reporting threshold of PERILS, CatIQ's parent company.
The steady rise in residential losses reflects the way pluvial flood claims develop. Basement flooding claims take time to scope, contents and restoration costs build up, and disputes over the cause of the water can delay settlement.
For personal lines brokers, the concentration of losses is the key point. When more than 45% of a market-wide personal lines loss comes from two postal districts, insurers' pricing and appetite in those areas is likely to come under pressure. Brokers with clients in Nepean and southwest Ottawa should expect closer scrutiny of water endorsements at renewal, and possibly higher deductibles or sublimits in the most affected neighbourhoods.
The Ottawa claims also show the gap between sewer backup and overland flood cover. Pluvial flooding can enter a home through both routes. A client with only one endorsement may find part of their claim isn't covered. Reviewing both, and pointing clients to the City of Ottawa's flood mitigation incentives, gives brokers a practical way to approach renewal conversations in affected areas.
