Tuesday’s severe storm produced an EF-2 tornado that reached 1.3 kilometres in width and created a 19-km path near Lucknow as well as downbursts that caused destruction in both Port Elgin and Southampton.
Those are among the findings of Western University’s Northern Tornadoes Project, which sent two teams of investigators to Huron and Bruce counties Wednesday to survey damage in the wake of the afternoon storm.
“A fast-moving line of storms overtook a smaller, slower-moving line, resulting in the development of an embedded supercell over Lake Huron. The supercell generated a multi-vortex tornado, plus several weaker ‘satellite’ tornadoes and downbursts, as it came onshore,” the organization said Friday.
The investigative teams completed both ground and drone surveys, collected photos and videos, spoke with storm chasers and analyzed radar information to create their preliminary report on the storm.
Witnesses in Port Albert and Point Clark, in the southwestern corner of Bruce County, captured video footage and photographs of a number of tornadoes from the same supercell storm over Lake Huron around 4:30 p.m. before the storm came ashore.
A preliminary review of data confirmed at least one tornado path, with the twister assessed as an EF-2 on the Enhanced Fujita (EF) scale.
The twister had a maximum wind speed of 180 kilometres per hour, a track length of 19 km and a maximum path width of 1.3 km, the NTP said in a report. Tornado motion was from the west.
The same supercell continued to move inland and reintensified as it approached Harriston, generating a second, EF1 tornado, at about 5:20 p.m. The same line of storms also produced an EF0 twister south of Goderich.
Also around 4:30 p.m., a “bow echo” embedded in the line of storms over Lake Huron produced downbursts as it came ashore at Southampton and Port Elgin.
Damage from those downbursts has been rated as EF-0 and EF-1 on the Enhanced Fujita scale.
EF0 twisters have wind speeds of 90 to 130 km/h, while an EF-1 tornado has wind speeds of 135 to 175 km/h.
No injuries have been reported from the storm.