The rare tornado outbreak that brought 37 twisters to Canada and the U.S.

Randi MannDigital Reporter

Published on Sep. 21, 2021, 9:10 AM

Updated on Sep. 21, 2022, 9:00 AM

On this day in weather history, a tornado outbreak hit the United States and Canada.

This Day In Weather History is a daily podcast by Chris Mei from The Weather Network, featuring stories about people, communities and events and how weather impacted them.

Between September 20 - 21, 2018, 37 hit areas of the United States and Canada, including Ohio, Iowa, Minnesota, Wisconsin, eastern Ontario, and southern Quebec.

On Sep. 20, a warm front in an unstable air mass popped up ahead of a lofty cold front. That evening, a convective system produced several tornadoes across Minnesota. An EF2 tornado caused widespread damage in the town of Morristown, and another one of the same strength damaged an airport in Faribault. Additional tornadoes were confirmed in Iowa, Wisconsin, and Ohio.

Dunrobin, Ontario. Courtesy of TWN.

A total of 25 confirmed tornadoes hit Minnesota, making it the state's third-most prolific tornado day on record.

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On Sep. 21, the warm air mass reached Ontario, bringing thunderstorms and torrential downpours. That afternoon, tornadoes hit eastern Ontario and southern Quebec. Seven tornadoes were confirmed between Ottawa, Ontario and Gatineau, Quebec.

Dunrobin, Ontario. Courtesy of TWN.

The most significant destructive tornado hit the community of Dunrobin in Ottawa. The tornado crossed the Ottawa River and travelled across Hull. The tornado was classified as an EF3 funnel, with winds reaching 265 km/h. As a result of the tornado, 25 people were injured.

In the Ottawa-Gatineau area, around 200 buildings were damaged.

Dunrobin, Ontario. Courtesy of TWN.

Another tornado, rated EF2, hit residential areas of Nepean. The other five tornadoes to hit the area were less destructive but took down power lines and damaged trees.

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The outbreak snapped around 80 to 90 Hydro poles in the area, causing power outages from more than 300,000 customers.

Beyond the widespread destruction, the tornado outbreak is significant because it hit so late in the year. Late sep. is usually hurricane season, and tornadoes have taken a back seat. But in 2018, 37 tornadoes were confirmed, including 1 EF3 and 2 EF2 funnels.

To learn more about the 2018 United States–Canada tornado outbreak, listen to today's episode of "This Day In Weather History."