THUNDER BAY — The extreme weather event that tore shingles off roofs and downed numerous large trees in a southside Thunder Bay neighbourhood brought wind gusts at least as strong as 91 km/hr.
That's what was recorded by an Environment Canada monitoring station at Thunder Bay Airport, but it's possible there were even higher wind speeds.
"I wouldn't be surprised if, within the neighbourhoods where the damage was the worst, the winds were maybe even a bit stronger than that," meteorologist Crawford Luke told Newswatch on Wednesday.
Luke said the evidence left by the thunderstorm that wreaked havoc in the Westfort area in particular indicates it was likely a downburst that caused the damage.
"In a thunderstorm, you have an updraft and a downdraft. A downburst is basically when you have a really strong downdraft. This is basically a lot of air rushing to the surface from the middle of the storm. Because it gets colder than its surroundings – and cold air sinks because it's denser – as it gets toward the ground it accelerates. Once it hits the ground it kind of goes 'splat' if you will, and shoots out in all directions. That's the wind we end up feeling from it."
He said the storm developed around Shabaqua Corners and tracked southeast to the city.
Environment Canada recorded the first lightning strikes around 4:48 p.m. Tuesday, with the most extreme wind gust occurring at 5:06 p.m.
By 5:24 p.m., the thunderstorm had moved out to Lake Superior.
