It could take several days to dig out from a major winter storm that has already closed schools across the GTA and upended holiday travel plans for some Torontonians.

Mayor John Tory delivered the warning during a news conference at city hall on Friday, noting that because of the rain that pelted the city overnight crews have been unable to treat roads with salt as they ordinarily would ahead of a major snow event.

He said that winds that are expected to gust up to 90 kilometres an hour on Saturday could also further complicate clean-up efforts, even after the snow subsides.

“People should be on notice with this storm, if it lives up to expectations, the clearing of snow will likely be a multi-day event,” Tory said. “That is not because there won’t be passes made through the different neighbourhoods right away but with the winds that are expected, for example, the snow will blow back onto the streets and will require plowing to be done again.”

Environment Canada says that Toronto will receive five to 15 centimetres of total snowfall accumulation between Friday and Saturday morning.

It is also warning of “potential flash freeze” conditions as temperatures plummet on Friday morning and the rain gives way to snow.

The weather agency says that conditions will be even more treacherous in southern Niagara, Niagara Falls and Welland, where it is warning of "crippling blizzard conditions" with 25 to 50 centimtres of snow accumulation and winds that could reach 120 kilometres an hour.

All of the publicly-funded school boards in the Greater Toronto Area have cancelled classes for the day, taking the somewhat rare step of making the announcement the day before.

Meanwhile, the city has positioned snow removal equipment at strategic locations across the city so that crews are able to quickly begin plowing and salting the roads as soon as conditions worsen.

There is also sufficient staff on standby to operate all 1,100 pieces of snow removal equipment in the city’s fleet simultaneously, if necessary.

“All my contractors have confirmed to me that there is staff available for all equipment so that when we make the call, they will be ready to go,” Toronto’s Director of Transportation Operations and Maintenance Vincent Sferrazza told reporters. “Having said that, this is going to be a multi-day, multi-round event. We anticipate that this will continue into next week, with the vast majority of the work happening today, tomorrow and into Sunday.” 

The city is asking residents to avoid parking on local roads during and after the snowfall “if possible” in order to help expedite the cleanup efforts.

So far the impact on public transit has been minimal but the TTC has suspended service on the Scarborough RT. Tory said that 41 bus stops on hills have also been taken out of service as a precaution.

“I encourage Torontonians to watch for updates from Environment Canada and to please be safe. The best thing probably that you can do over the next day or two or three is to stay home,” he said. 

Winter storm

Storm already impacting travel

The messy mix of winter weather headed for the GTA has already resulted in significant headaches for travellers hoping to fly home for the holidays.

WestJet has had to cancel all flights in and out of Toronto Pearson International Airport on Friday.

In a statement released on Thursday night, the airline called its decision to cancel dozens of flights just ahead of Christmas “extremely difficult” but said that it is taking “a proactive and measured approach” to protect its operations and “prioritize recovery flying this weekend.”

Other airlines continue to fly for now but are warning travellers to check their flight status before heading to the airport. 

Air Canada has also said that a temporary policy it has put in place will allow travellers to cancel any flight between today and Dec. 26 and receive a full refund. 

As of 4 p.m., the Greater Toronto Airports Authority said that nearly 40 per cent of all flights scheduled to depart or arrive at Pearson today have already been cancelled.

“I would say that today is probably one of the highest cancellations rates we have seen but that is due to WestJet’s operations and the decision they have made,” Greater Toronto Airports Authority spokesperson Tori Gass told CP24 on Friday. “Otherwise, we are doing pretty good still here at Pearson. The weather has started and it is not having that big of an impact yet. Our plows are out there and are already in action trying to keep all those runways open so our operations can be maintained.”

Gass said that many of the delays occurring at Pearson so far today are the result of major storm systems hitting Vancouver and in many U.S. cities where a lot of flights “are just not getting out today.”

However, Gass expects Saturday to be a better situation at Pearson airport because the weather conditions haven't been as significant as predicted.

"The forecast has changed quite a bit. And we think that we're going to have a fairly normal operation tomorrow aside from the airlines having to still kind of recover from any other cancellations that they saw, but I think we've been very lucky here at Pearson," she told CP24 Friday afternoon. 

"The blowing snow has meant that we've been having to clear the runways a lot. But we didn't get as much of it as we were expecting. We didn't really get the flash freeze that was expected," she added.

Numerous collisions

The rain began transitioning to snow in many parts of the GTA at around 9 a.m., quickly creating slippery road conditions and hazards in many areas.

Shortly before 4 p.m., Toronto police responded to reports of a hazard at a building at University Avenue and Dundas Street. Police said construction equipment had become dislodged and caused damage to the area. 

"That immediate area has been blocked off to pedestrians and vehicular traffic. We are urging the public that if anyone has to go out, please proceed with caution," Const. Jenniferjit Sidhu told CP24 Friday.

Earlier on Friday more than 100 vehicles were involved in multiple collisions on Highway 401 west of London.

Traffic was halted along a 100-kilometre stretch of the highway as crews tried to untangle the mess. The OPP also closed down Highway 402 in its entirety due to poor road conditions.

“It is just a big mess out there right now,” OPP Sgt. Kerry Schmidt told CP24. “I don’t have reports of any serious injuries but as officers are responding to crashes more crashes are happening behind them as vehicles plow into stopped traffic.”