Woodbridge, ON F2 Tornado of August 20, 2009

York - Durham

The F2 tornado in the Woodbridge neighbourhood of Vaughan, Ontario. The first of two strong tornadoes which struck Vaughan, this one touched down at 6:05pm and tore through the Woodbridge community in the southwest corner of the city. It was 100m in width and tracked for 9.6km through the dense neighbourhood, damaging hundreds of houses, several of which were totally demolished; garages were destroyed, windows shattered and roofs ripped off. In addition, trees and power poles were snapped and cars flipped and tossed.

Witnesses captured photos and videos of the tornado, a debris-filled cone tornado that caused constant power flashes as it tore through the neighbourhood.

Figure 1 depicts a line of severe thunderstorms entering southwestern Ontario from Michigan. These thunderstorms were responsible for the tornado outbreak on this day.

Figure 1. Doppler radar imagery at 3:38 pm EDT on August 20, 2009 (Source: Meteologix)

Figure 2 depicts the surface observations at 5:00 pm EDT, which shows a cold front moving through the Great Lakes and a warm front in central Ontario. The warm sector (southern Ontario), brought southerly winds moving across the open waters of Lake Ontario and Lake Erie. The advancing cold front and possible interactions with lake-breeze boundaries developed pre-frontal storms across southwestern Ontario, which moved east and brought one of the most significant tornado outbreak in Ontario’s history.

Figure 2. Surface analysis at 21Z on August 20, 2009 showing mean sea-level pressure (MSLP) contours, surface observations, fronts and pressure centres (WPC, 2017)

According to Environment and Climate Change Canada (2018), an F2 tornado touched down at 6:05 pm in Woodbridge, ON. The tornado travelled for 9.62 km, but its width was not documented by ECCC. The tornado caused no fatalities, injuries or property damage.


NWS Weather Prediction Center Surface Analysis Archive. (2017). Surface analysis 21Z Thu Aug 20 2009. 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/