The tornado that formed near Carstairs, Alta., on Canada Day was the strongest one the province has seen since 1987, Environment and Climate Change Canada (ECCC) said in a preliminary report Tuesday.
The tornado was rated as EF-4, with wind speeds estimated up to 275 km/h, according to ECCC.
It started with a thunderstorm that developed near Sundre and intensified as it moved closer to the Didsbury area, ECCC said, with the first reports of a tornado touching down coming around 1:45 p.m.
“The tornado appeared to weaken briefly before re-intensifying as it moved east,” said the weather agency.
The tornado track is more than half a kilometre wide and 15 kilometres long, ECCC reported.
“The heaviest damage — EF-4 — was reported where the tornado crossed Highway 2A between Didsbury and Carstairs,” said ECCC.
It said a “well-constructed” home was destroyed there, with all exterior and above-grade interior walls knocked down while the homeowner sheltered in the basement.
LISTEN: Storm chaser Kyle Hetherington describes his encounter with Saturday’s tornado on This Morning with J’lyn Nye and Daryl McIntyre
“This was a beast of a tornado,” said Tiffany Lizée, Global Calgary’s chief meteorologist.
Saturday’s tornado damaged 12 homes, three of which were destroyed and four left uninhabitable, ECCC said.
“Just to put this into perspective, this tornado flipped a combine, and combines usually weigh about 10,000 kilograms, so it tossed that combine quite a ways,” Lizée said.
RCMP said 25 cows and 20 chickens were killed in the tornado and one horse had to be put down. No people died and one person suffered minor injuries as she was pulled from the rubble of her destroyed home after she took shelter in the basement, police said.
“It could have been so much worse, but this is still really bad for those families who lost their homes,” said Lizée.
About 30 minutes after it formed, the tornado weakened and dissipated as it reached Highway 2, ECCC said.
ECCC said only eight other recorded tornadoes in Alberta have had a rating of EF-3 or higher.
“They do happen, they can get to this strength, but it’s certainly not something that we see every year,” said Lizée.
She added there have been 21 “violent tornadoes” recorded across Canada, mostly in southern Ontario, and the most recent one in Alberta was in Pine Lake in 2000 with wind speeds up to 266 km/h.
ECCC said Alberta typically sees 15 tornadoes per year — based on data from 1980 to 2009 — and so far this year, the province has already had up to 13.
–With a file from Dean Bennett, The Canadian Press