Likely a landspout type tornado, this one appeared during rapidly darkening skies and was witnessed by local farmers as a smoky plume of dust and debris. It destroyed an old barn near Wheatley where minor tree damage was also reported. Another similar tornado was reported 15 minutes earlier in Florence, about 70 km to the northeast.
Figure 1 depicts the surface map at 2:00 pm EDT depicting a strong low pressure system moving over the Great Lakes. The cold front and possibly lake-breeze interactions from the southerly flow moving over Lake Erie triggered thunderstorms across southern Ontario on October 4th.
According to Environment and Climate Change Canada (2018), an F1 tornado touched down at 3:45 pm EDT near Wheatly, 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 18Z Fri Oct 4 1985. 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/