Saturday storms produced three tornadoes near Goderich, tornado researchers confirm

A strong supercell thunderstorm that crossed parts of southwestern Ontario on Saturday produced three separate tornadoes in the span of an hour, researchers with Western University's Northern Tornadoes Project confirmed Monday.

All three tornadoes spawned between 6:30 p.m. and 7:30 p.m. on Saturday near Goderich as the storm system came ashore from Lake Huron.

The first tornado occurred on the lake as a waterspout, about 14 kilometres northwest of Bayfield, according to coordinates provided by Northern Tornadoes Project (NTP).

"Then it weakened a bit, and once it got on shore, it started producing a tornado again at Porter's Hill ... then it intensified again and produced another tornado further inland near Harlock," said David Sills, NTP's director.

The three tornadoes produced minor damage on land, and have been classified as EF-0 in strength, the weakest rating on the enhanced Fujita scale. No injuries have been reported, Sills said.

NTP conducted a ground and drone survey of the area on Sunday to document damage and to chart the paths of the two land tornadoes.

"The one bit of structural damage we know about from the tornado near Porter's Hill was a structure that had its roof peeled back," along Sharpes Creek Line, Sills said. Damage to a coverall building and to trees was also reported.

That twister had wind speeds of at least 124 km/h, and travelled 6.24 kilometres with a maximum path width of 190 metres, he said.

"The other tornado that hit Harlock was really impressive visually, but only produced weak damage — basically 90 km/h, a few tree branches broken," he said. It travelled nearly 4.7 kilometres with a maximum path width of 330 metres.

CBC News spoke with several residents on Sunday who recalled there being a calm before the storm's quick arrival.

"We sat down to have dinner, and all of a sudden my mom was like, 'You need to get to your safe place,'" said Deobrah Caira who lives near Blyth in the area where the third tornado touched down.

"I said, 'It's all clear and sunny outside.' Sure enough, I looked outside, and I saw this cloud formation rotating, coming toward us."

A short time later, the family took cover in the home's centre hallway as the tornado ripped by their property. "The doors were shaking on their hinges. The whole house was shaking," Caira said.

The passing tornado dissipated through a field behind the family's property, but not before it damaged a 150-year-old tree and tossed Caira's roadside vegetable stand down the driveway.

"There was a bit of confusion ... because there was a large marine tornado warning issued as the tornado over the lake was happening. I think quite a few people on shore got that warning," Sills said.

"But as the tornado moved onshore, there didn't appear to be a tornado warning issued then. When it came on shore, I don't think there was any warning or watch in effect, at that point."

The three tornadoes followed an EF-1 rated downburst that occurred in Mitchell on Thursday which damaged several barns, power pole, trees, and crops.