Heavy snowfall has blanketed the city as Toronto gets its first snowstorm of the year.

Environment Canada is calling for between five and 10 centimetres of snowfall throughout the day with as much as 15 centimetres of total accumulation by tonight.

The national weather agency says higher snowfall amounts will likely be seen in western parts of the city and snow is expected to be heavy at times in areas near the west end of Lake Ontario.

"Rapidly accumulating snow may make travel difficult. Visibility may be suddenly reduced at times in heavy snow and local blowing snow. There may be a significant impact on rush hour traffic," Environment Canada's winter weather travel advisory read.

Eric Holmes, a spokesperson for the City of Toronto's transportation department, said staff have been preparing for the weather event since this weekend.

"Whenever we get prepared for a snowstorm, a significant snowfall, work starts early. We started over the weekend tracking this snow event," he told CP24 on Tuesday. "Yesterday we really seemed to understand better how much snow we were going to get."

He said anti-ice trucks have already gone out to bridges, hills, and expressways to help prevent snow from sticking immediately to the roads.

Snow began to fly shortly after 9 a.m. in Toronto's downtown core.

"It's going to be intense, probably," Holmes said.

"As soon as the snow starts to accumulate on the roads, you are going to see the salt trucks out and they are going to make rounds to make the roads as safe as possible. We are going to continue to track the snow throughout the day. We are going to adapt the plan as we need to."

Snow plows will hit expressways after 2.5 centimetres of accumulation, main roads after five centimetres of accumulation, and local streets after eight centimetres of accumulation.

The snow is expected to taper off overnight as more frigid temperatures settle in for the rest of the week.

Environment Canada is calling for a high of -3 C on Wednesday but the temperature will feel closer to -13 with the wind chill.