WestJet proactively cancelled flights at airports in British Columbia, Ontario, and Quebec Thursday night as storm systems bore down on the regions, deepening a cascade of disruptions that have sent travellers scrambling.

Diederik Pen, WestJet's chief operations officer, said the decision to stand down 243 more flights was extremely difficult but necessary, in order to fly safely with as little disruption as possible when the weather improves.

"The prolonged and extreme weather events that continue to impact multiple regions across Canada are unlike anything we’ve experienced," Pen said in a statement Thursday.

The cancellations apply to all flights arriving and departing Toronto's Pearson International Airport Friday from 9 a.m. eastern time until the end of the day. 

Flights to and from Vancouver International Airport from 11:50 p.m. Pacific time on Thursday through late Friday afternoon were also off the books. 

Other airports affected by the service disruptions include those in Ottawa, London, Ont., Waterloo, Ont., Montreal, Victoria, Abbotsford, B.C., Nanaimo, B.C., and Comox, B.C. 

The airline was one of many still working to recover operations amid a series of storm systems and cold temperatures across the United States and Canada, including heavy snow that paralyzed Vancouver's airport early this week. 

The frigid cold in British Columbia could lift by Christmas, but not before delivering another blast of snow Thursday night. There was also the potential for freezing rain.

In Eastern Canada, rain, snow, flash freezing and strong winds were all in the forecast from Thursday through Saturday. 

The threat of more weather chaos hung over travellers Thursday struggling to return to loved ones in time for Christmas.

Maryanna Watts of Ancaster, Ont., had been trying to make her way to her daughter Kate in Squamish, B.C., for two days. 

She spoke on the phone from Winnipeg's airport, where she and her family unexpectedly found themselves Thursday, long after their direct flight from Toronto to Vancouver was cancelled.

"I've never been caught in this kind of situation in all my years of travelling," she said. 

Watts woke up Tuesday morning to a notification that her flight from Toronto to Vancouver was delayed, then cancelled. 

The family was eventually assigned a new route with a stop in Ottawa, but as they were putting on their baggage tags in Toronto, they received a notification that the Ottawa-Vancouver leg was cancelled too.

After an hour and a half on hold with Air Canada, they were offered rerouting through Mexico City with a one-night layover, or the flight via Winnipeg, which they accepted.

"We understand the weather, we live in Canada, we've been through all this weather before. But it's the lack of support when you need to talk to somebody. The communication has been really bad."

Hoping to head in the opposite direction was Toronto resident Emily Levict, returning from a trip to Australia with her brother and a friend. The group was stuck in Vancouver after their flight home Thursday was cancelled.

Struggling to find a way back to Toronto, the siblings are now booked on separate flights.

But Levict was not confident as she queued to find out more details about the rescheduling.

"Maybe we will make Christmas Day, but we will definitely miss Christmas Eve," she said.

In the meantime, more bad weather was heading for Ontario.

Rain starting Thursday night in Toronto will shift to flurries as a cold front moves in, said Peter Kimbell, an Ontario-based warning preparedness meteorologist with Environment Canada.

The front will rapidly push the mercury below freezing and bring strong southwesterly winds, creating messy conditions for Christmas travel. Roads will be icy and blowing snow will cause poor visibility, Kimbell said.

Just two to four centimetres of snow is projected in Toronto, but the strong winds will be the key factor for travellers throughout southern Ontario, he said.

Ottawa was expecting the potential of up to 15 centimetres of snow Thursday night before precipitation shifts to "slush" and freezing temperatures return later Friday, Kimbell said.

The same projections apply for Montreal, he said.

Cold temperatures, strong winds and flurries were expected to continue Saturday, gradually decreasing in intensity before easing further on Monday, he said.

Conditions improved Thursday at Vancouver International Airport, where 100 of 660 flights were cancelled, president and CEO Tamara Vrooman told a press conference. 

After some passengers sat on the tarmac for hours Tuesday, Vrooman said the airport had adjusted its de-icing schedules and gating protocols to avoid the "unacceptable" situation again.

It was on track to lift a two-day cancellation of international arrivals at 5 a.m. Friday, but Vrooman encouraged travellers to check with their carriers. 

The main focus now is on preparing for another wallop of bad weather, she said. 

Environment Canada predicted heavy snow, ice pellets and freezing rain in Metro Vancouver, Vancouver Island and the Fraser Valley starting Thursday night through Christmas Eve, followed by heavy rain as temperatures spike upwards.

"We are prepared and I'm confident in our preparations. But as you know, the province of British Columbia has just issued notice advising people of the severe weather coming and so we all need to be prepared."

Transportation Minister Rob Fleming told a news conference the significance of the incoming weather front cannot be overstated, as he urged against any non-essential travel across much of southern B.C. 

Vrooman said the freezing rain, in particular, could create challenges at the airport. 

"We have been watching the forecast for the freezing rain very, very actively because of course, it's one thing to have snow and snow removed. De-icing on freezing rain is very, very difficult."

Louie Madlang had slept three nights on the floor at Vancouver's airport as he tried to get home to Lloydminster, Sask., where his teenage son was waiting. 

He had been stuck at the airport since arriving Monday on a flight from the Philippines when his connection was cancelled.

Madlang, travelling with his wife and his adult nephew's young family, said he was now hoping to get a flight to Edmonton on Christmas Eve, then drive several hours home.

"We can’t shower and we tried to book the nearby hotels and they are all booked. We slept on floors or sometimes walked around in the airport for hours until (we) felt tired. As adults, we can handle that, but the most difficult is the kids,” said Madlang.

Difficulties linked to Tuesday's storm remained an issue at Victoria International Airport as a post from the International Civil Aviation Organization said two runways were still closed due to snow.

Hundreds of Air Canada and WestJet flights have been grounded since Sunday because of the conditions.

A statement from Air Canada said just over 88 per cent of planned flights went ahead Wednesday. With more severe weather in the forecast, affecting airports across Canada, the airline said it has a "flexible rebooking policy" in place, offering passengers the option to reschedule or receive a travel voucher.

The winter storm forecast for Ontario also prompted the postponement of the Ottawa Senators' game Friday night against the Detroit Red Wings.

Anthony LeBlanc, the Senators' president of business operations, said in a statement the safety of "players, fans, staff and those working at the arena is our first priority."

The Toronto District School Board said on social media that all of its schools and those of the Catholic board would be closed Friday.

All four publicly funded school boards in Ottawa will also be closed Friday due to the extreme weather forecast. 

— By Amy Smart, Nono Shen and Brenna Owen in Vancouver, with files from Cindy Tran in Ottawa

This story was produced with the financial assistance of the Meta and Canadian Press News Fellowship.

This report by The Canadian Press was first published Dec. 22, 2022.