Tornado at Bloor and Yonge

by Joey deVilla on August 20, 2009

Tornadoes normally don’t come ‘round our way here in Accordion City, but today’s storm system was quite unusual. Out here in the High Park area, it turned the sky wasabi green and smack in the middle of town, a proper tornado formed. Local YouTube user “Tubocracy” shot this footage:

{ 9 comments… read them below or add one }

Chris Taylor August 20, 2009 at 8:38 pm

Definitely a well-formed wall cloud… I don’t see any tornadoes though. The Pearson METAR didn’t report any funnels either.

darryl August 20, 2009 at 10:00 pm

I was sitting quietly in my downtown apartment, watching the lightning flashing in the distance, when suddenly — wind and rain came screaming through my open window (it faces the balcony, so this was serious sideways rain). Literally blew my blinds off. Scared the crap out of the cat, who was sleeping soundly underneath the window.

If that wasn’t some type of tornado, I’d like to know what you’d call that.

MaryL August 20, 2009 at 10:11 pm

Joey, I really doubt that was a tornado. That person and no one else, AFAIK, is making the claim. Those were some damn dynamic clouds and storming, though. I’m a couple of kilometres north of you and I was seriously eyeing my basement during the worst of it.

H. August 20, 2009 at 10:22 pm

I was biking west on Argyle (near Dundas/Ossington) looking west, and then Humbert, and I saw a perfectly formed funnel, a distance away and quite high up in the sky. Also the sky was green. It may have not touched down, but there were funnel clouds in the west, in the high park area.

Chris Taylor August 21, 2009 at 10:52 am

It’s not unusual to get winds gusts of 50-65kts (93-120kph) in severe thunderstorms. That would be more than sufficient to dislodge blinds and do serious damage to property. Thunderstorms are perfectly capable of trashing more firmly-anchored stuff (like trees) even without tornadoes.

darryl August 21, 2009 at 4:35 pm

In my 44 years I’ve seen my share of wind gusts. This wasn’t like anything I’ve seen before.

Wind gusts are typically associated with lower-intensity winds. It was perfectly calm — which is why my cat was still sleeping soundly, and I left the window open.

I live near Yonge and Bloor, on the eight floor, so when I saw that funnel video, it made sense what likely happened.

I agree, for “some form of tornado” it was a wimpy one. Blowing off my blinds was nothing like blowing down a house. But there’s no way that was simply a thunderstorm.

Chris Taylor August 21, 2009 at 6:50 pm

Sorry Darryl… I don’t know where you took your meteorology but gusts are not lower-intensity winds.

Wind gusts occur in hurricanes, too. They are a pedestrian way of saying “peak wind speed”. Every thunderstorm generates what is known as a “gust front” at the outflow boundarywhich has at least some level of wind shear, and they are a normal part of any storm cell. What varies is the peak wind speed and severity. The gust front is hazardous to aircraft because of the sudden wind shift and intensity, so one may safely imagine it is hazardous to your blinds as well.

Most people conflate storm wind damage with tornadic winds, but the vast majority of damage can be safely attributed to the high outflow winds (150+ kph) that can occur in severe thunderstorms.

Incidentally, to be classified as a “severe” thunderstorm, the cell must generate gusts of 50kts or greater. Guess what kind of thunderstorm warning was generated for the GTA on August 20th. That’s right, a severe thunderstorm warning; so that storm had already been clocked with peak wind speeds of at least 50kts (93kph) before it got anywhere near us.

darryl August 28, 2009 at 3:07 pm

Chris, if you’re still reading this, thank you for the education.

One question though. The wall that’s about 15 feet from my window was spattered by that gust. Not by the floor, but about 3- 6 feet up, the same height as my window. As I was wiping off the dirt, it occurred to me — if I’m on the 8th floor, and rain falls from the sky, where does the dirt come from?

Chris Taylor September 23, 2009 at 9:37 am

Sorry I didn’t get to this earlier.

The short answer is that the dirt in rain is picked up by normal convection activity (i.e. sun heating air, warm air rising and meeting cooler air, forming clouds, etc). Dust, pollen, salt, plus the airborne pollutants of an urban environment get carried aloft by winds, stay aloft due to the updraft of convection, and then they start collecting moisture. You might say at the heart of every raindrop is a speck of pollen or dust.

As it collects more moisture it will eventually get heavy enough to overpower the convective updraft, at which point it falls as rain.

How dirty it is depends on how forceful that convective updraft is, and how much crap is available to be carried aloft. We have a lot of dust and dirt (and pollution) in Toronto. =)

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