Bruce Mines, ON F1 Tornado of July 4, 1999

Sault Ste. Marie - Superior East

This tornado destroyed a century-old barn and snapped and uprooted trees. It tore the heavy steel doors off of a quonset hut and threw them up to 1 km away. In addition, a trailer was flipped, a boat was thrown and farm equipment was scattered. This was one of two tornadoes to touch down in the province on July 4; the other was an F0 near Thunder Bay.

Figure 1 depicts the surface observations at 8:00 pm, which shows a stationary front near Sault Ste. Marie. This front was responsible for thunderstorms and ultimately this F1 tornado.

Figure 1. Surface analysis at 00Z on July 5, 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 F1 tornado touched down at 11:20 pm EDT near Bruce Mines, 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 00Z Mon Jul 5 1999. Retrieved from:

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