Environment Canada explains timing of Essex tornado alert, as experts weigh in

A storm prompted a tornado warning on June 5 at 12:32 a.m., which many residents say came after the worst of the weather had passed. (Tetyana Linnik/Getty Images/iStockphoto)

Following concerns from Essex residents about the timing of a tornado warning earlier this month, Environment Canada is explaining the science behind how and when such alerts are issued.

It comes as the Town of Essex formally moves forward with a request for answers, approving a motion this week to ask Environment and Climate Change Canada (ECCC) to clarify how its alerts are triggered and whether southern Essex County has adequate radar coverage.

The June 5 storm prompted a tornado warning at 12:32 a.m., which many residents say came after the worst of the weather had passed.

According to ECCC, that alert followed a severe thunderstorm warning issued at 12:03 a.m., when the storm was over Harrow and tracking northeast.

“Tornado Warnings are issued by ECCC when there is evidence that a tornado has developed or may form imminently,” said spokesperson Hannah Boonstra in a statement to CTV News.

She said meteorologists “always strive to provide the best lead-time possible with all warnings and use all available observation data to inform their decisions.”

Boonstra explained that Essex County is primarily covered by radar in Exeter, Ontario, with additional data used from neighbouring U.S. radar systems to help forecasters monitor developing storms.

“ECCC is continually enhancing its weather services,” she added, “taking full advantage of the latest technology to upgrade the tools used to predict and relay information about the weather to Canadians.”

Essex Mayor Sherry Bondy says the storm and the delayed alert have reinforced the need for timely communication in the region.

“We know Windsor-Essex County; we’re surrounded by water. We’re surrounded by the Great Lakes, the river,” said Bondy.

“We know that there’s storms here that can be quite volatile, and we need accurate information.”

She says she’s hopeful the town’s outreach will lead to more than just a written response.

“Maybe there’s a relationship where in Essex we offer some municipal property for them to use to put more infrastructure,” said Bondy.

“One of the hardest things” to forecast

CTV News also spoke with David Sills, director of Western University’s Northern Tornadoes Project, who said tornado warnings are notoriously difficult to issue with precision.

“Tornadoes are very difficult to warn for,” he said.

“Every second counts when it comes to tornado warnings.”

Sills said his team evaluates the performance of Environment Canada’s warnings each year, and while they’ve improved slightly, there’s still room to grow.

“They’ve been improving the last few times we’ve done the report card,” he said.

“But, you know, there’s a lot of work left to do.”

He noted that the target lead time for a tornado warning is only about ten minutes — making fast, accurate alerts a constant challenge for forecasters.

“It’s really one of the hardest things as a forecaster, dealing with tornadoes and tornado warnings,” he said.

Tornado risk remains high in Ontario

In 2024, Ontario led the country in tornado activity, with 60 tornadoes confirmed across the province, according to the Northern Tornadoes Project.

Among them was Canada’s first tornado of the year — an EF0 landspout that touched down in Malden Centre, right in Essex County, on March 16, 2024.

It tied a record for Ontario’s earliest confirmed tornado on record.

The rising number of verified tornadoes in recent years is due in part to improved radar coverage and enhanced investigations by the Northern Tornadoes Project, which uses satellite imagery, drone surveys and ground reports to confirm and classify events.

While most tornadoes are weak and short-lived, Bondy says they still present serious risk and require timely communication tools.

“We haven’t yet heard back [from Environment Canada], but I’ve heard back from residents that they need to do more,” she said.

“We need to have a good working relationship with Environment Canada so that we can trust and rely.”