The City of Montreal launched its first major snow-clearing operation of the year Wednesday morning.

More than 2,000 vehicles are cleaning snow off the city's 10,000 km of streets and sidewalks.

Drivers are being warned to pay attention to signs indicating snow clearing is imminent or they will be towed.

Meanwhile, a second fast-moving system will bring more rain and snow to the region. Freezing rain arrived Tuesday evening as temperatures dipped overnight.

Another 2 to 4 cm of snow is expected to fall in Montreal Wednesday, with 5 to 10 in the Eastern Townships, before the temperature will begin a steep decline, expected to reach an overnight low of -20 C Thursday, and be even colder overnight Friday.