Sheppardton, ON F0 Tornado of July 17, 2004

Huron - Perth

Near Sheppardton, the tornado knocked over shallow-rooted trees, tossed lawn furniture and caused minor structural damage to a cabin which was moved a short distance. The tornado was on the ground for 400 metres and was 30 metres wide.

Figure 1 depicts the surface observations at 2:00 pm EDT, which shows a stationary front over Lake Ontario and a trough over Lake Erie. The interactions between lake-breezes generated by Lake Huron and the convergence from these fronts likely initiated thunderstorms on the shores of Lake Huron, which ultimately led to this F0 tornado.

Figure 1. Surface analysis at 18Z on July 17, 2004 showing mean sea-level pressure (MSLP) contours, surface observations, fronts and pressure centres (WPC, 2017)

According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 3:00 pm near Sheppardton, ON. The tornado travelled for 500 metres and had a maximum width of 30 metres. The tornado caused no fatalities, injuries or property damage.


NWS Weather Prediction Center Surface Analysis Archive. (2017). Surface analysis 18Z Sat Jul 17 2004. Retrieved from:

Environment and Climate Change Canada Data. (2018). Canadian National Tornado Database: Verified Events (1980-2009) – Public. Retrieved from: