The Northern Tornadoes Project has released a report into Tuesday's severe weather system that stormed through midwestern Ontario about 4:45pm Tuesday.
A report says 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 storm caused significant tree and structural damage from Kingsbridge east to south of Lucknow. There were no injuries.
Preliminary data confirms at least one EF2 tornado with winds speeds of up to 180 km/hr travelled 19 km with a path width up to 1.3 km.
Further investigation is pending