A prolonged, significant period of freezing rain is forecast in and around Ottawa-Gatineau from Wednesday afternoon through Thursday morning.
Environment Canada has issued a freezing rain warning for a vast area encompassing Petawawa east to Montreal, and Maniwaki south to Brockville.
The storm could bring five to 10 millimetres of icy precipitation, setting the conditions for dangerous travel and power outages.
Freezing rain is predicted to start between 5 and 6 p.m. in Ottawa and fall for the next 12 hours.
The warnings include Kingston and Belleville,Ont., where freezing rain is expected to begin in the afternoon and end in the evening. Up to five millimetres is expected in that region, with rain falling closer to Lake Ontario.
In Renfrew County, a few hours of freezing rain is expected Wednesday evening. In western Quebec, more freezing rain could come Friday.
City crews working to salt sidewalks, roads
Bryden Denyes, a manager with the City of Ottawa's roads department, said crews are monitoring the incoming storm and will be applying salt on roadways and sidewalks as they become icy.
"I would expect later in the evening the commute to be a little bit slow," Denyes said, adding that could pose some delays for crews.
"That means our equipment, the trucks and sidewalks machines out working, are stuck in traffic as well," he said.
Ice coats a crosswalk sensor in Ottawa last January after a freezing rain warning. A prolonged period of freezing rain is expected into early Thursday morning. (Matthew Kupfer/CBC)
Crews are expected to continue working overnight, and Denyes said priority roadways will be in decent shape by morning.
"But when you get into potentially some sidewalks and our residential streets, there could be some ice accumulation still left on those," he added.
Ottawa has had a warmer January than usual, with a mild start followed by more seasonal temperatures.
Daytime highs are forecast above 0 C Thursday, Friday and Saturday.
The National Capital Commission, which manages the Rideau Canal Skateway, announced the attraction will be temporarily closed starting Wednesday evening. A section of the skateway opened for the first time this season on Sunday.
This closure will "preserve the ice during the forecasted warmer temperatures and rain," the NCC said on social media.