Cornwall, ON F0 Tornado of July 6, 1999

Cornwall - Morrisburg

This tornado was observed and reported by CANWARN storm Spotters as it touched down at 2:30 pm near Cornwall, in Eastern Ontario. No damage was done.

Figure 1 depicts surface observations at 2:00 pm, which shows a low pressure system over James Bay with a cold front extending into southern Ontario. This cold front triggered thunderstorms in eastern Ontario, which ultimately led to this F0 tornado.

Figure 1. Surface analysis at 18Z on July 6, 1999 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 2:30 pm EDT near Cornwall 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 18Z Tue Jul 6 1999. Retrieved from:

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