A barrage of freezing rain, snow and wind across Ontario knocked out power and forced roads, schools and businesses to close in some regions Wednesday.

Whiteout conditions prompted police to shut down most highways and roads in three southwestern Ontario counties. Provincial police said all municipal and county roads and highways were shut down in Dufferin, Grey and Bruce counties.

Port Elgin, Kincardine, Meaford, Flesherton and Durham are among the cities and towns cut off from surrounding communities. Municipal offices, schools and businesses in the affected areas are also closed for the day because of blowing snow.

The City of Toronto called an extreme cold weather alert, which will stay in effect until further notice.
   
The alert opens an additional 80 emergency shelter spaces in Toronto, as well as an extended outreach effort which sees additional vans patrolling city streets overnight checking on homeless people and providing them with transportation to shelter.

TTC tickets are also made available at drop-in centres to help homeless people reach shelters.

Police also closed two eastern Ontario bridges: The Norris Whitney (Bay) Bridge linking Belleville and Rossmore and the Skyway Bridge linking Tyendinega and the Municipality of Prince Edward.

Several other highways in the province were also closed, including stretches of Highways 17 and 11 in northern Ontario.

In the south, a wind warning covered Windsor to the Quebec border, with gusts of over 100 km/h expected in some regions. The wind was blamed for power outages affecting some 25,000 Hydro One customers in several communities, and prompted the ferry to shut down between Kingston, Ont., and Wolfe Island.

There was a flash freeze warning from the London area to Quebec as a fast-moving cold front caused temperatures to plummet, and a freezing rain warning covered Ottawa and far eastern Ontario.

Temperatures in eastern Ontario were expected to drop from 0 C to -9 C by the evening.

Environment Canada has also posted wind chill and winter storm warnings in northern Ontario from Kenora to the North Bay region.

Whiteout conditions have already prompted police to close Hwy. 17 between Sault Ste. Marie and Blind River and Highway 11 between Hearst and Kapuskasing.