Saying the video evidence leaves no doubt Wednesday night's severe weather event was a tornado, Weather Preparedness Meteorologist Geoff Coulson says investigators will answer two questions.
First, how strong was the tornado that touched down in LaSalle and Windsor? And second, was it one tornado, or two?
An answer is expected either late Thursday afternoon or evening.
Coulson, who works for Environment Canada, says the damage left behind can tell investigators a lot.
"If we have significant roof damage done to structures, that moves us into the EF-1 [Enhanced Fujita scale] range where the winds peak at 175 km/hr," he says. "If the roofs have been totally removed and perhaps a wall is coming down, we're getting up into the EF-2 scale."
An EF-2 tornado has peak winds of up to 220 km/hr. At the top, an EF-5 event has peak winds of up to 376 km/hr.
In LaSalle, the winds blew the roofs off two homes on Victory St. In Windsor, 15 homes suffered damage on Riberdy Rd.
"Preliminary estimates from some of the pictures I've seen given damage in the EC Row Exwy. and Central Ave. area of Windsor would indicate at least into the EF-1 scale," says Coulson.
Coulson says the storm that spawned the tornado was relatively mild until it hit the Detroit River. At that point, it intensified quickly, and the twister touched down just off the LaSalle marina.