Southern Ontario Tornado Outbreak of 2009

At one point, over 10 million people in Southern Ontario, one-third of Canada's population, were placed under tornado watches and/or warnings as the storms rolled through.

During the afternoon of August 20, 2009, a series of supercell thunderstorms began to develop over southeast Michigan, increasing in number as they moved into western sections of Southwestern Ontario.

The tornado weakened and continued through more rural areas before striking the town of Markdale, where F0 damage occurred to homes and trees.

An isolated cell produced a tornado that swept across the Royal Riding Academy, in a rural area east of Newmarket.

[1] The first tornado was at its most powerful as it passed through the southeast section of Durham, causing serious structural damage to several businesses in the town's small industrial park, including the complete destruction of a press plant.

Passing through the northeastern part of town, the tornado hit a conservation area where a children's day camp was taking place.

The tornado hurled debris from a gatehouse and other buildings and trees onto a tent structure where the children and counselors were seeking shelter.

[4] Although damage to homes and the resort was extensive, perhaps the greatest economic toll was to the owners of local apple orchards, which were severely affected.

The tornadic storm responsible for the [[ Grey County]] tornadoes weakened as it went over the lake, having traveled and sustained its intensity for, according to Environment Canada, "a remarkable 200km.

"[1] In the Barrie area, two farm homes were partially unroofed, a shed collapsed, and a heavy trailer was picked and moved a distance of over 100 m (330 ft).

The first of the Vaughan tornadoes hit the Woodbridge neighbourhood in the southwest part of the city, flipping cars, damaging dozens of homes - many severely - as well as numerous businesses and a school.

The second tornado struck the Maple neighbourhood in the northeast part of the city, causing a 2.7 km (1.7 mi) long path of damage to dozens of homes.

[1] In the hours after the tornadoes touched down, a state of emergency was declared in the city of Vaughan[14][15] and in West Grey, including the town of Durham.

Given their intensity and urban setting, particularly the tornadoes at Vaughan, the outbreak garnered media attention unlike any other in recent years.