Premier Dalton McGuinty has announced that the Ontario government will allocate $5 million to a disaster relief fund to help Goderich, Ont., after a powerful tornado ripped through the town's centre on Sunday.

McGuinty said the funds will be put toward cleanup, recovery, and to help homeowners and businesses in cases where their own insurance won't cover the damages.

"You're not alone," McGuinty said in a Monday afternoon news conference, adding that 13 million Ontario residents are behind them. "We are with you and want you to take heart. We want you to know that we are in your corner."

Environment Canada has confirmed that the tornado that ripped through Goderich, Ont., on Sunday afternoon — causing massive damage and killing a man, as well as injuring dozens — was an F3.

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"This is the worst damage I've ever seen," Environment Canada's Randy Mawson, who has been investigating storms for 36 years, said on Monday afternoon.

Winds of roughly 280 km/h carved a path about 500 metres wide at one point through the town's centre, he added.

"To the south of that and to the north of that, if you go far enough, you'll see no damage occurring, but along that 500-metre path through the downtown core, quite a bit of damage," he said.

McGuinty, who thanked the town's leadership and emergency responders, said it was the most extensive devastation he'd seen in 21 years of public office.

"This is not a matter from which you recover overnight," he said. "There is going to be some serious reconstruction involved."

The premier said the first priority will be to make sure the town is safe and secure and that the power is restored. After that, the long-term rebuild will begin, he said. He seemed to leave the door open to more funding if necessary, saying that the province will see where the $5 million "gets us, and we'll take it from there."

Tornado was on the ground for 20 km

The tornado was on the ground on Sunday afternoon for approximately 20 kilometres, Environment Canada said.

It killed Norman Laberge, 61, of Lucknow, Ont., who was working in a salt mine, and injured at least 37 people. Thunderstorm warnings were in place and a tornado warning was issued for 3:48 p.m. ET — just 12 minutes before it struck, CBC meteorologist Johanna Wagstaffe said.

Goderich, a community of about 8,000 that's renowned for its beautiful sunsets, parks and beaches, is on the eastern shore of Lake Huron about 225 kilometres west of Toronto.

Residents awoke Monday to downed trees, crushed cars and businesses reduced to rubble after the tornado ripped through the downtown core.

"Canada's Prettiest Town," as the town's official website calls it, is now in a state of emergency.

Access to the downtown area is blocked off, and police have closed all entrances to the town for safety reasons and likely to discourage looting, says CBC's Dan Sherman, reporting down the shoreline in Bayfield, because of the restricted access.

Mayor Delbert Shewfelt vowed to repair the damage.

"Words are not enough to describe the destruction," he said. "It's unbelievable. That's all I can say."

Windshields 'blown out'

Some witnesses to Sunday's storm described cars being picked up and tossed like toys.

Sherman said resident Bob Earnest recalled hearing what he thought was a jet plane flying too low. He became disoriented, and then the side and back windshields of his vehicle were "blown out" by the tornado.

Herb Marshall, the owner of the Park House Bar and Restaurant, said the scene was right out of the movies.

The Fujita scale The strength of a tornadoes in Canada is measured by the Fujita scale, which estimates wind speed inside a tornado based on the damage that's observed. The scale, which was devised in 1971 by University of Chicago researcher Tetsuya Fujita, pegs F3s at between 253 km/h and 330 km/h. Typical damage includes walls and roofs destroyed, collapsed metal buildings and destroyed forests.

"[The storm] came up the hill off the lake ... and just took everything with it," Marshall said. "I believe I saw a garbage bin up in the air going by."

Cassandra Phillips-Grande, 16, said that she was in a coffee shop in the town square when the wind started to pick up. She said she tried to help some of the injured, including people suffering from gashes and things falling on them.

"We saw tables and chairs outside of the café flying and then saw an SUV roll like a tumbleweed right in front," she said, adding that everyone in the shop moved to the back of the building.

"About two seconds later, we heard this really big crash and the roof collapsed in the spot where we had all been. When we went outside, we saw that some apartments had collapsed right in front of the café."

Sherman reported that the community began pulling together shortly after the mighty storm toppled the town.

At the local Knights of Columbus Hall quickly became a relief centre Sunday night, feeding storm victims and repair crews.

"Goderich may have taken a hit, but the resiliency of this community is evident," Sherman reported. "Everyone is doing what needs to be done and pulling together."

It may be some time before Goderich is restored to its pristine beauty, but townspeople are determined to pick up the pieces, and live up to its vows to visitors to its official website that, "Once you visit Goderich, your heart will never leave."