This tornado developed as a waterspout over Lake Erie at 11:30am, then moved ashore and travelled for 5 km with a path that was 100m wide. Witnesses captured photographs of the twister, a highly photogenic cone tornado that was classic in appearance and fully condensed to the ground.
A house was shifted slightly off of its foundation and had windows shattered, as well as shingles and siding torn off. A shed was destroyed, farm equipment scattered, crops were levelled and trees snapped and uprooted.
This was one of three tornadoes that touched down in Southern Ontario on August 4; the others were an F1 on Hamilton Mountain, and an F2 that struck Flamborough and Burlington.
Figure 2 depicts the surface observations at 2:00 pm, which shows a low pressure system exiting Ontario with a cold front across Lake Erie. The low pressure would have brought southwesterly winds across Toronto and Hamilton, which could have activated the lake-breezes across Lake Ontario. Figure 2 depicts an ongoing thunderstorm over Hamilton (marked as an “R”), which is responsible for this F1 tornado.
According to Environment and Climate Change Canada (2018), an F1 tornado touched down at 11:30 am EDT near Clear Creek, ON. The tornado travelled for 5 km with a maximum width of 100 metres. The tornado caused no fatalities or injuries, but caused $75 thousand dollars in property damage.
Sources
Michiel, B. (August 4, 1999). York University: Tornadoes of Southern Ontario. Retrieved from: http://www.yorku.ca/pat/research/dsills/tornpix/tornadoes.html
NWS Weather Prediction Center Surface Analysis Archive. (2017). Surface analysis 18Z Wed Aug 4 1999. Retrieved from: https://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive.php
Environment and Climate Change Canada Data. (2018). Canadian National Tornado Database: Verified Events (1980-2009) – Public. Retrieved from: http://donnees.ec.gc.ca/data/weather/products/canadian-national-tornado-database-verified-events-1980-2009-public/