An aerial view of homes in Vaughan, Ont., that were ravaged when a tornado touched down in the city north of Toronto on Thursday. (Darren Calabrese/Canadian Press)

The state of emergency has been lifted in a Toronto suburb that was hit hard by a series of tornadoes on Thursday that damaged about 600 homes.

The twisters rendered unlivable about 44 of the homes in Vaughan, north of Toronto. Those homes will have to be demolished.

Mayor Linda Jackson said police and fire services will remain in the affected areas until Monday morning, and she encouraged people who haven't boarded up damaged dwellings to do so.

Earlier Saturday, federal Public Safety Minister Peter Van Loan toured the area and said a decision on whether federal aid will be granted will be made in the coming days.

"It's not a political thing. It's a complex mathematical formula," Van Loan said.

Van Loan said municipalities and provinces have the initial responsibility in emergency situations, adding that the federal government will help "when we can."

The fact that damage was not as extensive as it could have been, given the intensity of the storms, is a testament to the area's emergency response teams, Van Loan said.

"This site is in a lot better shape now than it was even 12 hours ago," he said. "In this case they applied the [emergency response] plan, they used it and it worked perfectly."

An 11-year-old boy died at the Durham Conservation Area, about 50 kilometres south of Owen Sound, during the storm. At the family's request, the boy has not been identified. Police have declined to provide further information on the death, but it is believed the boy was killed by debris.

Environment Canada has confirmed that four tornadoes hit Southern Ontario on Aug. 20. Three of the tornadoes have been classified as f2 damage on the Fujita Scale. F2 damage is equivalent to wind strength of 180 to 250 km/h. Environment Canada lists two other twisters spotted that day as "probable."