Environment Canada is warning residents of southern Ontario and Quebec to brace for a winter storm.
The federal forecaster says a low-pressure system around the Great Lakes could dump snow on parts of Ontario starting Sunday night, while a storm brewing in the United States is making its way to southern Quebec.
Snowfall and storm warnings are in effect across much of Ontario, with regions, including Niagara, Kingston and Ottawa, told to expect as much as 40 centimetres between Sunday night and Monday evening.
The Ottawa-Carleton District School Board told parents Sunday night that students would continue to learn remotely Monday because of the weather, instead of resuming in-person classes as scheduled.
The provincial government temporarily moved schools online after the winter holiday because of the Omicron variant of COVID-19, and had said classrooms would reopen on Monday.
The Toronto District School Board is also warning that a snow day is possible Monday, and says that if that happens, students should plan to attend classes remotely.
The weather agency says the Greater Toronto Area should prepare for up to 20 centimetres of snow, along with wind gusts as strong as 60 kilometres per hour, and commuters should expect dicey roads on Monday morning.
Quebec, meanwhile, can expect to see up to 35 centimetres of snow in some regions, including the Laurentians.
Snow is expected to start falling in the province overnight Sunday and early Monday.