Rannoch, ON F0 Tornado of July 18, 1990

Huron - Perth

This tornado occurred at 7:45 pm, and tore a path through rural properties near the cross-roads community of Rannoch, to the west of St. Marys. It snapped and uprooted trees, flipped a trailer and damaged farm buildings.

Figure 1 depicts a significant ejecting low pressure near Hudson Bay with its associated cold front and warm front at 5:00 pm EDT. Since the tornado occurred at 7:45 pm EDT, storms were likely “pre-frontal” ahead of the cold front, likely initiated by the pre-frontal trough.

Figure 1. Surface analysis at 21Z on July 18, 1990 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 7:45 pm EDT near Rannoch, ON. The track and width of the tornado was not documented by ECCC. The tornado caused no injuries, fatalities or property damage.


NWS Weather Prediction Center Surface Analysis Archive. (2017). Surface analysis 21Z Tue Jul 18 1990. 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/