Gallagher Re has issued a preliminary loss estimate for the September 2 severe convective storm that hit the Greater Toronto Area, projecting that insured losses will reach "well into the hundreds of millions" of dollars, with the total economic toll higher still once uninsured and underinsured losses are factored in.
The estimate is based on the storm's combination of large hail, damaging straight-line winds, and flash flooding across one of Canada's most densely populated and highest-value property corridors.
Half reached golf-ball size, 4.5 centimetres, across much of the urbanized GTA, with the largest stones northwest of downtown, in and near Vaughan and North York, likely exceeding 6.3 centimetres in diameter. Rainfall in similar areas ranged from 50 to over 100 millimetres, quickly overwhelming roadways.
At the peak, at least 150,000 Ontario customers lost power, and Toronto Fire Services responded to nearly 1,500 calls in the 24 hours surrounding the storm, among the department's highest call volumes on record. Rogers Stadium in North York, the Gardiner Expressway, Bayview Avenue, and the Don Valley Parkway all sustained significant impact, and the storm system extended into the US Northeast, generating hundreds of additional straight-line wind reports across New York, Pennsylvania and the Mid-Atlantic.
Gallagher Re's report placed this event in a broader trend worth flagging directly to clients: five of the past six years have produced billion-dollar-plus annual aggregate severe convective storm losses for Canadian insurers, with hail as the dominant driver, mirroring a pattern also seen in the US.
The current record year remains 2024, at US$2.8 billion ($3.8 billion), driven mainly by the August Calgary hailstorm, which alone cost insurers US$2.5 billion. That Calgary event's own loss estimate has since been finalized by CatIQ at a stable $3.349 billion two years post-event, with more than 95% of claims resolved, giving the industry a precise, closed benchmark for what a genuinely severe Canadian hail catastrophe ultimately costs once fully adjusted.
While Alberta's Hail Alley remains Canada's dominant hail-loss region, Gallagher Re noted southern Ontario is a well-established secondary hotspot, particularly in late summer, which is exactly the pattern this event confirms.
What distinguishes this GTA event from a Prairie hail loss is population and property density. A comparable hailstorm striking a less urbanized region generates a fraction of the exposure of the same storm tracking through Vaughan, North York and downtown Toronto simultaneously, where high-value residential and commercial properties, dense vehicle concentrations, and major infrastructure like Rogers Stadium and multiple expressways all sit inside the same damage footprint.
That concentration is precisely why Gallagher Re's preliminary language points toward the higher end of the loss range rather than a moderate regional event.
This event's claims volume pressure is already showing up in the market. Reporting since the storm has described flood, hail, wind and fallen-tree claims piling onto an already-strained Ontario claims system, adding to a summer that has produced repeated significant weather events across the province.
Brokers with commercial clients in the Vaughan and North York corridor specifically, where the largest hail fell, should treat vehicle fleet exposure and building envelope damage (roofing, facades) as priority claims categories given Gallagher Re's specific mention of both.
For clients with exposure near Rogers Stadium or other large commercial and entertainment venues in the affected footprint, business interruption and event-related coverage questions should be raised proactively rather than waiting for a formal loss estimate from CatIQ or IBC.
Gallagher Re's estimate is explicitly preliminary, and a more precise industry figure will likely come from CatIQ in the weeks ahead, following the same initial-estimate, 45-day, and multi-year revision pattern CatIQ has applied to other 2026 events this season.
Given that even Calgary's 2024 hailstorm took roughly two years to reach a fully stabilized final number, brokers should expect this GTA event's true cost to keep climbing through multiple revisions before landing on a final industry tally.
