On the afternoon of August 19, 2005, a line of severe thunderstorms tracked eastward across southern Ontario from Kitchener to Oshawa, including the northern half of Toronto.
At its worst, the system spawned two F2 tornadoes with gusts between 180 and 250 km/h.
The first tornado tracked through Milverton to Conestogo Lake (west of Elmira). The second moved from Salem to Lake Bellwood (north of Guelph).
The twisters uprooted hundreds of trees, downed power lines, tossed cars and trucks aside, and ripped into several homes, cottages and barns.
Meanwhile, a deluge of rain - over 100mm in parts of Toronto - and golf ball-sized hail caused flash floods, water main breaks and damage to infrastructure and property.
It was considered a once in a hundred-year storm. Insured losses exceeded 500 million Canadian dollars.
"This Day In Weather History” is a daily podcast by The Weather Network that features unique and informative stories from host Chris Mei. Click here to listen and subscribe!