Thousands of southern Ontario homes and businesses remained in the dark days after destructive thunderstorms that one expert says highlighted the gaps in extreme weather preparedness.

High winds ripped out trees and tore down power lines while torrential rain dropped more than 100 millimetres in some areas on Sept. 2, flooding basements and major streets. Another powerful storm ripped through parts of southwestern Ontario the next day, including in Windsor where researchers were investigating a likely tornado. 

The storms underscored how unprepared many Ontario communities are for a climate marked by more frequent and intense extreme weather, said flood risk expert Jason Thistlethwaite, an associate professor at the University of Waterloo. 

“These do not seem like 100-year storms because they’re certainly happening with a lot more frequency than that,” he said. “They’re going to overwhelm our infrastructure the way it’s built today.” 

Toronto Hydro called the Sept. 2 storm one of the most significant in years as its crews worked to restore power to more than 2,000 customers still in the dark ahead of the long weekend. It said crews were handling broken utility poles and hundreds of reports of downed power lines.

Hydro One, the provincial utility, said roughly 10,000 of its customers, largely in southwestern Ontario, were without power after back-to-back storms rolled through some areas Wednesday and Thursday. 

The Northern Tornadoes Project said its crews were out in the Windsor area to survey what is likely tornado damage. The damage in Toronto was likely the result of downbursts, the researchers said. 

Among the most damaged structures was the 50,000-capacity Rogers Stadium in Toronto’s north end, where bleachers were ripped out by high winds that also left behind partially collapsed grandstands.

Toronto fire officials reported just shy of 1,500 calls over a 24-hour period, which they said was their second-highest call volume in a day, after the 2013 ice storm. City manager Paul Johnson called it a “100-year storm” that caused widespread destruction in Toronto and the surrounding areas. 

The repeated flooding seen across southern Ontario this summer highlights long-standing gaps in how governments prepare for extreme weather, Thistlethwaite said. Climate change, driven by the burning of fossil fuels, is making storms more intense and frequent. 

He said officials need to do more to disclose flood-risk information to homeowners and focus investments on neighbourhoods most vulnerable to flooding. 

He noted the federal government spent years developing public flood risk maps but has yet to release them after announcing earlier this year it would only provide them where the provincial government has opted in. So far, none have done so and the public search portal remains unusable. 

While some low-lying infrastructure, such as Toronto’s Don Valley Parkway, will likely continue to flood during major storms, more targeted investments can reduce the risk of costly damage to homes and businesses, Thistlethwaite said. For some high-risk homes, government buyout programs may eventually be on the table.

“We simply just cannot provide to keep sustaining the services and infrastructure in this particular location because the climate risk is just that high,” he said. 

“Once you find that 1% of risk, you’re also going to find areas that are safe and good to develop. And we need to focus on providing infrastructure to those places.” 

While local officials often face criticism after major floods, Thistlethwaite was sympathetic to municipalities who he says in many cases have flood mitigation plans but lack the money or political backing to act on them. 

He pointed to Toronto’s $3-billion stormwater sewer upgrades along the Don River and the waterfront as an example of the kind of major investments needed to adapt to a changing climate. 

“At the municipal level, there’s a tremendous and heightened sense of emergency,” he said. 

This report by The Canadian Press was first published Sept. 4, 2026.