In total, three F2 tornadoes touched down near Durham, Vaughan and Collingwood. Three F1 tornadoes touched down near Milton, Newmarket and Markdale. The Durham F2 tornado was responsible for the death of an 11 year old boy who was killed when the shed he had taken shelter in collapsed.
The F2 tornado near Vaughan caused significant damage including over 600 homes that were damaged or destroyed.
Thunderstorms were forecast across Southern Ontario Thursday afternoon and evening ahead of a cold front moving through the area. Cloud cover during the day was forecast to keep temperatures and humidity down but the clouds never materialized. Hot sunny conditions and high humidity helped to make the storms cells more potent and more dangerous.
Storm damage was not limited to funnel clouds but included hurricane strength winds and torrential rain with amounts estimated at about 30 mm. Damage reported included trees uprooted in Sarnia; roofs ripped off and a trailer overturned in Durham, likely connected to the tornado; power lines down across the area; pea sized hail; a car flipped over in Newmarket; and houses damaged in Woodbridge and Vaughan, likely associated with the tornado sighted there.