A huge snowstorm that caused flight cancellations and shut down schools in Ontario on Friday has hit Newfoundland. 

Heavy snowfall and high winds are forecast for Atlantic Canada, and in Newfoundland winter storm warnings are in effect for southwest, central and eastern regions.

Many flights in and out of St. John's International Airport for Saturday have been cancelled.

Driving conditions are deteriorating as snow builds up on the roads.

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Visibility on Pitts Memorial Drive is very poor Saturday afternoon as heavy snowfall hit St. John's. (Jane Adey/CBC)

Heavy snowfall and high winds are making driving conditions treacherous on the highways, as well as on residential roads.

In the Maritimes, two storms are colliding, causing power outages and flight cancellations. Nova Scotia and New Brunswick are expecting around 40 centimetres of snow.

Snow began to fall on the Burin Peninsula around 8:30 on Saturday morning, and shortly before noon in St. John's. The system is expected to change late tonight, into a long period of snow mixed with ice pellets.

CBC Meteorologist Ryan Snoddon said snow is expected to start in central areas Saturday afternoon. It will continue all night and through Sunday. Snoddon added that up to 45 centimetres is forecast.

Winds are anticipated to increase later this afternoon to between 50 and 70 kilometres per hour.

For the latest weather details, with a direct link to Environment Canada, visit Ryan Snoddon's blog: http://www.cbc.ca/ryansnoddon/