Imagine 10 million people, one-third of Canada's population, under a tornado watch or warning on the same day.
That's exactly what happened on August 20, 2009, when a line of severe thunderstorms swept across southern Ontario.
18 tornadoes touched down, making it the biggest one day tornado outbreak in Canadian history. Two F2 tornadoes struck the city of Vaughan and a state of emergency was declared.
"It only took 15 seconds, it went right between our houses, and next thing you know the roof is off and everything is leaking inside the house," said Vaughan resident John Fiore.
Others say there was no chance for rebuilding what was already there. Over 600 homes were damaged and some families were left homeless.
Two other F2 tornadoes struck in Grey County, one at Georgian Peaks Resort and one in Durham, where an 11-year-old boy lost his life.
It was a similar scene in Sudbury, Ontario on August 20, 1970. An F3 tornado left six people dead and caused $10 million worth of damage.
As each year passes, residents in the affected areas can't help but wonder if a similar outbreak will occur.
According to Chris Scott, a meteorologist at The Weather Network, it is a possibility.
"Severe weather doesn't have a ‘memory’ of what happened in previous years, so the odds of a tornado hitting Vaughan around this time of year are the same as before August 20th, 2009," he says. "Think of a casino slot machine. After every play, the machine resets, and the odds of getting a certain result are exactly the same as on the previous play."
TORNADO WARNING SIGNS
WHAT TO DO DURING A TORNADO