Ontario Provincial Police expect Highway 400 to reopenin time for the morning rush hour Tuesday morning, after a harsh dose of winter weather the previous day causedpileups involving more than 75 vehicles.

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Paramedics and firefighters remove a man from the wreckage of his tanker truck, which rear-ended a semi in a massive pileup on Hwy 400 north of Toronto on Monday. ((Bill Sandford/Canadian Press))

Sgt. Lorne Thompson of the OPP told CBC Newsworld that hazardous materialscrews had cleaned up propane spilled on the road by a wrecked tanker and were in the process of repairing the centre median.

"They've done quite a miraculous job with the drifting snow and they've been able to … get the job done within the short timeframe," he said. "[They] worked hard throughout the night and roads are looking a lot better than they were yesterday."

Highway 400 GO bus services were disrupted on Tuesday, the website of the interregional public transit system said as of 7:20 a.m. Some passengers who take buses from Barrie to King City will be dropped off at the Bradford GO station instead of King City, the website said.

GO was also reporting bus delays arriving and departing Toronto's Union Station on Tuesday, as the city's Gardiner Expressway remained closed as a precaution due to falling ice from the CN Tower.

On Monday afternoon, pileups closed Highway 400 south of Barrie, asblowing snow and powerful wind gusts caused accidents across southern Ontario.

OPP Const. Sally Stewart said police were aware ofat least one life-threatening injury and several serious injuries, but no fatalities.

"We have a lot of drifting snow and high winds today," Stewart said. "It makes[the snow] very loose and therefore the wind can pick it up and throw it around, which causes complete whiteouts."

Police closed ramps onto the 400 in the area of the pileupsas emergency crews worked to free people from the wreckage.

The northbound pileup happened near Highway 88.The southbound pileupwas farther north, near Highway 89.

'Sometimes we give tips about winter driving but when there's zero visibility, there really isn't a safe way to drive.'— OPP Sgt. Cam Woolley

The northbound accident, involving more than 30 cars, three trucks and two coach buses, was the most serious, according to CBC reporterSteven D'Souza. A truck driver and a van driver were taken to hospital with critical injuries. At least 35 others are in hospital with minor injuries.

Sections of Highway 400 near the accident scene are expected to remain closed until Tuesday morning.

Weather cancelsVia Rail service

Extreme weather forced Via Rail to cancel its train servicein parts of Southwestern Ontario.

Trainsbetween Kitchener and London were affected, with service to Brampton, Georgetown, Guelph, Kitchener, Stratford and St. Marys cancelled Monday night.

Service will not be provided to St. Marys or Stratford Tuesday morning.

While the weather disrupted trains, it also caused hundreds of minor accidents as snow and winds gusting up to 100 km/h pummelled the southern Ontario, hitting areas along Lake Huron and Georgian Bay the hardest.

Like 'driving in milk'

More than a dozen major highwaysacrosssouthern Ontariowere closed because of the blowing snow, with visibility down to half a kilometre in some spots.

OPPSgt. Cam Woolley suggested motorists avoid driving west of Highway 400, saying conditions are fluctuating between sunshine and whiteouts that make it feel like they're "driving in milk."

"Sometimes we give tips about winter driving but when there's zero visibility, there really isn't a safe way to drive," Woolley said.

The severe weather closed allcounty roads in Dufferin County, about 80 kilometres northwest of Toronto.

Police asked drivers not to skirt blocked highways by taking back roads, warning there is little chance of being found if something happens on the less-travelled routes.

"It's really a dangerous situation starting to build and it's getting worse," Woolley said.

Drivers can consult the Ontario Ministry of Transportation website for updates on road conditions and road closures. Via Rail updates are posted on the Via site.

With files from the Canadian Press