Vasey, ON F0 Tornado of July 11, 2003

Barrie - Orilla - Midland

Toppling a few trees and hydro poles, the tornado was witnessed by several people who described seeing a swirling cloud of debris. This was one of three tornadoes that developed out of low-topped supercells that crossed the Muskoka Region on July 11. The others were an F0 at Elmvale and an F0 near Bracebridge. Damage from the three tornadoes was estimated at around $50,000.

Figure 1 depicts the surface observations at 8:00 am EDT, which shows a low pressure over Lake Huron with a cold front extending into southwestern Ontario and a warm front extending into southern Ontario. These fronts became the focus of intense thunderstorms in the early morning hours of July 11th, which ultimately led to this tornado.

Figure 1. Surface analysis at 12Z on July 11, 2003 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 10:20 am EDT near Vasey, ON. The path and width of the tornado was not documented by ECCC. The tornado caused no fatalities, injuries or property damage.


NWS Weather Prediction Center Surface Analysis Archive. (2017). Surface analysis 12Z Fri Jul 11 2003. Retrieved from:

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