Studying the storm Scientists working to categorize, analyze Aug. 7 tornado By: Danielle Da Silva Posted: 7:00 PM CDT Monday, Aug. 10, 2020

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This article was published 09/08/2020 (1605 days ago), so information in it may no longer be current.

A deadly tornado that tore a path through southwest Manitoba Friday is the second severe twister to hit the region this summer, and weather scientists are analyzing a trove of evidence to learn more about it.

Following early damage assessments in partnership with the Northern Tornadoes Project, Environment and Climate Change Canada has preliminarily categorized the tornado as an EF-2 on the Enhanced Fujita scale. The scale rates twisters from zero to five, with five being the most severe.

According to the Northern Tornadoes Project, which is based out of Western University and aims to collect and analyze data on all tornadoes in Canada, the tornado that touched down near Scarth, 13 kilometres south of Virden on Friday left a 9.35-kilometre trail of damage in its wake, destroying land and property up to 740 metres away.

On June 28, an EF-2 tornado also hit Rapid City, Man., about 100 kilometres northeast of Scarth, reaching estimated wind speeds of 190 km/h and covering 5.6 kilometres of ground, toppling grain bins, levelling out buildings and scattering debris up to 200 metres away. No injuries were reported.

Alysa Pederson, a meteorologist with Environment Canada, said tornado events can’t be compared, but data on all verified tornadoes, between 1980 to 2009, were primarily classified as F-0 on the Fujita scale.

“A lot of tornadoes are quick spin-ups and F-0s because there is a lot of open space,” Pederson said. “That’s why it’s hard to compare any specific event.

“We can’t really speak specifically to any anomalous situations regarding tornadoes because it depends on what it hits,” she said.

So far this summer, four tornadoes have been recorded in Manitoba, three of which were confirmed, including an EF-0 tornado in the Kenville area on July 17 and one in Letellier on June 23.

Satellite images, video footage assisting weather scientists

Satellite imagery of Scarth collected by Planet.com the day after the deadly tornado touched down, and analyzed by NTP, shows the tornado’s path of destruction as it tracked northeast.

“This is actually the first time we were able to get a satellite image a day after a tornado,” said Gregory Kopp, a professor at Western University and ImpactWX chair in severe storms engineering. “In this case, there was scour, there were crops in the area and so as soon as there is crop damage, you can see it (the track) pretty clearly.

“The end of the track, as it was dissipating showed pretty clearly the damage,” he said.

A before and after comparison of satellite images can help assess the storm and its trajectory, Kopp said, and a team of engineers and meteorologists also consider photographic evidence, video and drone footage and evidence from the field when classifying a tornado.

His team is still trying to confirm where the tornado started, but evidence suggests it touched down west of Provincial Trunk Highway 83, south of Road 51 N, then proceeded past a farmhouse which was left intact, crossed the highway and tore through cropland before dissipating north of Road 51 N, over the span of 10 to 15 minutes.

“We are still investigating other damage details that we observed there,” Kopp said. “That EF-2 rating is truly preliminary. We try to get something to Environment Canada fairly quickly… and then we go back and try to assess it just with science, without all the emotion of the events so close.”

Pederson said the last fatal tornado occurred on Aug. 3, 2018 when a man was killed in Alonsa, Man. during an EF-4 tornado. Prior to that, a woman was killed during a tornado in Gull Lake in 2006.

A spokesman for Manitoba Public Insurance said 10 auto claims have been opened related to the tornado as of Monday afternoon. David Koroscil, manager of claims services with Manitoba Agricultural Services Corporation, said two claims have been opened for hail damage to crops.

“Early indications are there was not a lot of hail in the area associated with the storm, and actual crop damage directly as a result of the tornado would appear to be fairly minimal as well,” Koroscil said.

Kopp said a final classification for the tornado is expected within a week.

danielle.dasilva@freepress.mb.ca

Danielle Da Silva
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Danielle Da Silva is a general assignment reporter.

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