Friday, July 21, 2017
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As most of you know, I live in Fergus and have been observing weather and storms in the area for over 10 years. This page is as accurate an overview of the whole event as I can come up with. It is not a final or official report by the government and will be updated as new data becomes available. I hope it will help understand what happened and where. Thankfully, no one was seriously injured or killed. This aspect is taken from my point of view with pictures I have taken, some that have been sent to me and data and information many would never see otherwise. Although I chase storms, I never like to see damage occurring in dense populated areas much less near my friends and family.
On the evening of August 18th, I noticed the weather models were indicating that areas over southern Ontario were looking ripe for supercells to form in the afternoon of August 19th. These rotating storms/supercells would have the chance to produce tornadoes as they matured. I went to bed at 3 am and tossed and turned which is always a sign that I know something is going to happen. At 8 am I awoke to grey overcast skies and wondered if my forecast was accurate. The convective outlook from Environment Canada (EC from now on) had a small hint that tornadoes were possible.
I fired up the radar and looked at the computer models. Storms were starting to come across the region and should hit the Fergus area after 1pm. Around 10:19 am, a severe thunderstorm watch was issued for Wellington County and this was upgraded to a tornado watch at 12:50pm. At this time I was out the door on a course to intercept this storm to the west of Salem traveling along side road 15. At 1:11pm a severe thunderstorm warning was issued for Wellington County as I was coming into Salem. I got about 3 kms to the west of Salem when I had a complete electrical breakdown of my truck. My wipers stopped working. This was not good as it has happened twice before with the wipers and both times tornadoes have been really close or occurring.
I gave a quick call to George Kourounis and then Mark Robinson for some important data. While on the phone with Mark I told him I was seeing this storm wrapping up and getting really organized. He said to stay where I was and then wait for the rain to end and go home for repairs. This was around 1:30 pm. About 4 mins later the tornado hit Salem and reports started to come in. At 1:35pm, a tornado warning was issued on the storm for tornado damage in Conestoga Lake region. This was the same storm but a different part of the storm had created a new tornado as the old tornado spun out.
My chase was over but as I was crawling into Salem to get my truck fixed, I turned from a stormchaser to someone just there to document the event and help out.
The Tornado Scale
The Fergus F2 Tornado was rated on the Fujita Scale of Damage. This means that the winds are estimated based on how much damage is done to trees, structures etc. An overview of the Fujita scale is below.
This was a strong F2 and could possibly be re-rated an F3 after further analysis is done.
The Tornado's Statistical Data
It originated in Salem and tracked to the ENE to Fergus where is made a slight turn to the right almost due east which is very common with tornadic storms. It began this turn as it was the strongest and biggest. It then began to weaken and turn back to the ENE before dissipating near Belwood. It traveled 11kms and was 1.50 kms wide at it largest point just NE of Fergus. It was traveling around 50 kph as it moved over the area. The complete storm reports for the day are here.
The Tornado's Radar Images
I have compiled a complete account of the tornado in radar images for you to see the storm on a large scale that meterologists use to detect intense storms and tornadoes. Click the image for a large animation but they run about 1.5 megs each one for clarity and size. Now, the locations of the storms are off a little bit due to the tilt of the radar so the storm and tornado is actual about 2 or so kms south from where it is in the radar images (normal).
Storm Reflectivity Images
This image shows the storm in regards to precipitation intensity. You can also see the storms is rotating counterclockwise over the entire image. The spoke that wraps down over Salem is the beginning of the tornado and it starts to disappear when it begins to get near Belwood. This color index is on the left of the image and the stronger colors indicate the most intense part of the storm.
Storm Velocity Images
This image shows the storm in regards to to way the winds are moving to and from the radar station. If you look at the area near Salem at the start you can see the reds and greens very close together indicating rotating winds to and from and this is the signature you look for in rotation in storms. Although you can have this type of rotation in a storm that does not produce a tornado, that is not the case here. You can the storm was rotating just before Salem and then intensified as it traveled. If you look at the first 2 frames, you can see the same thing in the NW part of the image showing where the Conestoga lake was ending.
Storm Relative Velocity Images
This is another image that looks at the winds within storms. It shows a much stronger couplet and a more defined location of where the tornado was.
The Tornado's Damage
The follow map is a clickable one. All the points listed are images of damage along the path of the tornado with the areas as close as I can remember or get too. There are even a few aerial shots. They are some of the ones I took at the very beginning and some that people have sent in. I did not get a complete set of images as many areas were blocked off and I was too busy helping clear areas etc to bother with taking pictures or video. As it was a trying time, I never just start taking pictures without asking (my own rules when I chase). Some areas are still blocked off to public access so maybe more photos will come in the days and weeks and I will add them.
I should note that not one picture of the tornado was taken. After talking with people and looking at radar, it appears the tornado was wrapped in rain so that it was not visible to see. There are some images floating around on the net saying they are from the area when they are not. An example of the imposter photos is here!
Some aerial shots were taken of the storm by AerialFocus. They are copyrighted by them and on this site to give a larger picture of the storm damage. I know where one is taken but the others I am not familiar with.
If you have any interesting photos, stories etc and would like to send/share them, please send them to me and I will add them to this account.
All Images, graphics Etc are copyrighted Dave Patrick unless otherwise stated.
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