Family Day weekend drivers are being warned to take it easy on the roads.
Ottawa and much of southern and eastern Ontario is getting a serious dousing of freezing rain that could last up to six hours on Sunday.
Freezing rain and icy roads are already causing havoc across much of southern Ontario, making driving treacherous.
Ontario Provincial Police reopened both westbound and eastbound lanes of the 417 near Casslleman around 5:30 p.m. after closing them because of icy conditions.
Mandy Pollard of the OPP said that so many cars were sliding into ditches on that stretch of highway, the police decided to close it until salt trucks could get there.
"There are no injuries, but this just happens to be a very bad area. It's just sheer ice," she told CTV.
Highway 416 near
However, Police are urging extreme caution for those who do venture out.
Among major roads affected are Highways 401, 403 and the 407. Numerous crashes have already been reported, and the worst is yet to come.
According to Environment Canada, Ottawa and much of southern and eastern Ontario are under a winter storm warning because of a large-scale winter storm tracking northeast.
Environment Canada said the Ottawa area is expected to receive freezing rain for around three to four hours producing an icy coating of two to four millimetres before the temperature rises and the precipitation turns to rain.
However, it is possible that the freezing rain may persist longer - up to six hours - over portions of the Ottawa Valley as the colder air remains trapped in the valley.
With files from the Canadian Press
