Possible tornado as spring thunderstorms hit Ontario

Wednesday, April 12, 2017, 6:01 PM - Environment Canada continues to investigate the potential cause of significant storm damage in the London, Ont., area.

"Thunderstorms roared across parts of southwestern Ontario Tuesday afternoon, bringing strong and gusty winds, small hail, heavy downpours, and frequent lightning to a few localities," the agency said in a weather summary. "One thunderstorm briefly intensified Tuesday afternoon as it tracked just north of London toward Woodstock. This thunderstorm produced strong wind gusts that resulted in damage to a barn, some trees, and utility lines."

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After a team from The University of Western Ontario surveyed the wind damage, they concluded that the damage was the product of winds gusting up to 150 kilometres per hour, corresponding with an EF-1 rating, the agency said. Further analysis continues into the long weekend.

The Weather Network meteorologist Dayna Vettese was watching the rotating cell on radar at the time of the storm. It came with a system that moved across southwestern Ontario. No severe thunderstorm warnings or watches were issued in the region, however, photos posted on social media by a nature photographer Harry Schut show significant damage to a barn and uprooted trees northeast of London.

"Storms developed across southwestern and south central Ontario [Tuesday] afternoon," Vettese said. "One storm in particular formed west of the London area and tracked northeast just before 4 p.m. EDT."

"As [the storm] formed and matured, it began to take on a certain shape on radar that we typically recognize as a supercell thunderstorm," Vettese added. "Radar was indicating that the storm was rotating as it moved north of the London area toward north of the Woodstock area."

Vettese noted that the storm took on a "hook" shape that is often associated with rotation and a possible tornado.

"Soon after the storm moved through the region we saw a report from the Ontario Provincial Police that there was damage to some hydro poles just north of Thamesford, and this region correlated to the path the storm took through the area. We later learned of more damage done to a farmstead north of London’s airport. Once again, the damage was in the area that the storm tracked through. We received a couple of images via social media that showed a funnel cloud and suspect tornado associated with this storm. Environment Canada has sent out a damage survey team to assess the damage and determine if it was a tornado."

If confirmed, this will be the first tornado of 2017 for Canada. The earliest tornado on record for Ontario is one that touched down on March 16, 2016, when an EF-1 moved through a region northwest of Mount Forest.