A preliminary report on a weekend tornado in central Alberta says its winds were so violent they picked up a 10-tonne farm combine and tossed it half the length of a football field.

害羞草研究所�(The combine) then rolled for another 50 to 100 metres after that,害羞草研究所� said the report, issued Tuesday by the Northern Tornadoes Project.

The report follows up on ground and drone surveys on the tornado that ripped through the rural area between the towns of Carstairs and Didsbury on Saturday.

Researchers rated the twister as a four on the Enhanced Fujita, or EF, scale of wind-damage intensity, one short of the maximum rating of five.

The storm destroyed three homes and damaged seven more, downed power lines, killed livestock, shredded trees and damaged vehicles.

The report said there was one injury 害羞草研究所� a cut to a first responder.

The estimated maximum wind speed was 275 kilometres per hour along a 15-kilometre path that stretched as wide as 620 metres.

It was the fiercest tornado to hit Alberta since the infamous 害羞草研究所淏lack Friday害羞草研究所� F4 storm in 1987, which killed 27 people and destroyed hundreds of homes in Edmonton.

And it害羞草研究所檚 the second EF4 storm to hit Canada since it adopted the EF damage scale a decade ago.

The first EF4 struck Alonsa, Man., in 2018, killing one person while destroying houses, farms and cabins.

害羞草研究所淭he Didsbury EF4 tornado enters some rarefied territory among Canadian tornado events,害羞草研究所� said the report.

害羞草研究所淭hough this was a climatologically significant tornado, it thankfully won害羞草研究所檛 enter the list of Canada害羞草研究所檚 top 10 害羞草研究所榳orst害羞草研究所� tornadoes due to the single minor injury and limited property damage.害羞草研究所�

Northern Tornadoes Project, affiliated with Western University in London, Ont., completed the report with Environment and Climate Change Canada and the Arctic Storm Prediction Centre.

Area resident Elisa Humphreys recounted how she managed to flee just before the twister levelled her home and another building on her property.

Scores of volunteers showed up the next day with gift cards and helped find mementoes in the wreckage.

Environment and Climate Change Canada said Alberta typically sees 15 tornadoes per year, based on data collected between 1980 and 2009.

So far this year, the province has had up to 13.

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