A tornado that touched down in rural Alberta on Thursday levelled an entire home and damaged at least four others, while other parts of the province were pelted with hail as big as hen eggs.
The affected homes were located in the small community of Bergen, in Mountain View County, south of Sundre. The funnel cloud was spotted on Thursday afternoon, as severe thunderstorms hit central and southern Alberta. Environment Canada said it received reports of tornadoes in the area over the course of about 40 minutes. The agency said a full assessment will need to be completed to determine whether there were several tornadoes, or only one.
Angela Aalbers, the reeve of Mountain View County, drove through the affected area on Friday morning. She said the destruction is “just incredible,” with uprooted trees and debris strewn across streets. The forest around some homes has been completely destroyed, she added, and the majority of outbuildings at one residence are beyond repair.
“It’s just a horrible sight to see,” she said. “This is not a normal thing. We see funnel clouds every once in a while, but we’ve never actually had, that I can remember, a touchdown of a tornado within the county.”
Cleanup efforts are continuing in the region. Ms. Aalbers said she had no estimate of how long they will take.
A preliminary report posted by Environment Canada on Friday said winds in Calgary reached speeds of 104 kilometres an hour during the storm. Hail was reported in seven areas across the province, and it ranged from two to five centimetres in diameter. Severe thunderstorm watches remained in effect on Friday.
Thunderstorms are common in Alberta, but only 10 to 15 tornadoes are recorded in the province each year. Environment Canada meteorologist Terri Lang attributed their rarity to the fact that the right mix of conditions is seldom in place.
“This storm came out of what we call a supercell, which is a rotating, very organized type of thunderstorm,” she said. “The things that we need for that are humidity, heat and the winds in the upper atmosphere to be changing direction and speed throughout the atmosphere, which allows the storm to start rotating.”
Environment Canada is working with members of Western University’s Northern Tornadoes Project to survey the damage.
Lesley Elliott, a research meteorologist with the project, said preliminary observations suggest the Bergen tornado was an EF1, the second-weakest rating on the Enhanced Fujita scale, which categorizes the intensity of tornadoes based on the severity of the damage they do. The EF1 category describes damage caused by wind speeds between 135 and 175 kilometres an hour. Ms. Elliott said the Bergen tornado was likely at the upper end of that range.
She said extreme weather events, such as droughts, wildfires and heavy rainfall, are expected to increase as a result of climate change. She added that it is unclear whether tornadoes will be affected, but that it is possible the timing or duration of peak tornado season could shift.
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