By Kristy Nease, CBC News Ottawa, September 29, 2018
(...)Tornadoes in Ontario
Environment Canada's tornado database contains information from only the past 37 years. During that time, the way twisters have been confirmed and analyzed has changed drastically, right up to 2017, with the introduction of new, specialized satellite imaging.
On average, nearly 13 confirmed and probable tornadoes occur annually in Ontario, but the figure is a bit misleading, according to Environment Canada meteorologist Peter Kimbell.
The last few years have been relatively quiet, with 10 in 2017, 11 in 2016 and nine in 2015. Some years have seen a lot more, such as 2013, when there were 23, and 2009, when there were 35.https://newsinteractives.cbc.ca/longform/ottawa-gatineau-tornado-storm-2018