Montrealers cope Wednesday with the first snowstorm of the season, which is expected to leave more than 30 centimetres behind. (Paul Chiasson/Canadian Press)Montreal has been slammed by the season's first snowstorm as weather experts predict a dump of up to 30 centimetres by Thursday morning.

The snow will continue to fall overnight, warned Environment Canada meteorologist André Cantin.

"We should have by tomorrow morning a total of 25 to 30 centimetres on the ground," Cantin said.

On Wednesday, some schools were closed and flights in and out of Montreal were delayed or cancelled.

Visibility was poor on the province’s roads, provoking some accidents, though none with serious injuries, provincial police said.

About 20 cars were involved in an accident on Highway 40 near Berthierville around 2 p.m. Wednesday. The accident left 10 people with minor injuries.

In Montreal, motorists needed patience to get home through the rush hour.

Patience was also needed for public transit users relying on the Orange Line of the Montreal Metro. Subway service was stopped for about 45 minutes during rush hour because of a technical problem.

The City of Montreal said it was prepared for the storm.Montreal's Berri-UQAM Metro station is packed with commuters as subway service resumes. (Justin Hayward/CBC)

The city’s director of snow removal services, Yves Girard, said plowing began as soon as 2.5 centimetres of snow had fallen.

"We'll start with the plowing equipment on streets and sidewalks," Girard said. "If we get the precipitation we expect, we will start the snow-removal operation with 3,000 employees who'll work for four or five days, depending on the snow we receive."

The city has bought 12 additional sidewalk plows for snow-clearing in the downtown district, he said.

Authorities have also identified 15 priority bus routes that will be cleared first, and will try to co-ordinate with boroughs as much as possible, Girard added.

Officials urged people to use public transit if they can, leave work early or stay home, if possible, and take it easy on the roads. The city says snow removal could take up to four days, once the storm passes.

Officials at Trudeau International Airport urged people travelling Wednesday to check with their airlines before heading to suburban Dorval.Montreal's director of snow removal services, Yves Girard said the city was prepared for the storm. (CBC)

There was a scramble at some garages Wednesday morning as last-minute drivers showed up to have snow tires installed.

The lineup at Gordon's Garage in Montreal started at 6 a.m. Those who arrived after 9:30 a.m. were turned away.

"People wait to the last minute and it is tough on us," said mechanic Matt Loiseau. "But the people in the front office like it."

A new law enacted last year in Quebec makes it mandatory for drivers to have snow tires on their vehicles from Dec. 15 to March 15.

Flu vaccination slowed

The Montreal Health Agency announced it was closing most of its flu vaccination centres Wednesday because of the storm.

Officials said only the centres that can be reached by the Metro will remain open.

Those centres include:

• Olympic Stadium.
• Alexis-Nihon shopping centre.
• Palais des Congrès.
• UQAM's Hubert-Aquin Pavilion (closes at 7 p.m.).

The storm has already left parts of the United States under a thick blanket of snow.