After a day of springlike temperatures, winter's wrath returned, creating hazardous driving conditions across the city.

Up to 15 centimeters of snow fell in Toronto on Wednesday, according to Environment Canada. Temperature is expected to plunge to a low of -17 C tonight, the weather agency predicts. With the wind chill, it will feel more like -31 C.

As the low pressure system heading northeast from Indiana passed through the GTA, dozens of minor collisions were reported by Ontario Provincial Police.

OPP cautioned drivers that the combination of snow, warm temperatures and wind would slow down traffic and impair visibility.

In a message on Twitter, the OPP advised drivers to turn on their lights, give themselves extra time and avoid distractions like cellphones.

On Wednesday morning, a Durham Region Transit bus and a pick-up truck collided, causing the bus to get stuck in a ravine on Nichol Avenue and Thickson Road in Whitby. The 46-year-old Stouffville man who was driving truck was taken to hospital, where he later succumbed to his injuries. Three passengers and the driver were on board the bus at the time, but Durham police told CTV Toronto that there were no serious injuries.

Meanwhile, a snow plow flipped on its side Stouffville Road just east of Highway 404, York Regional Police said. The eastbound lane of Stouffville Road was temporarily closed from Highway 404 to Woodbine Avenue as police worked with tow-truck drivers and crane operators to right the vehicle. The driver has minor injuries.

A 61-year-old woman died after she crashed her car at 14th Avenue and Ninth Line in Markham. She was rushed to hospital without vital signs.

Dozens of flights cancelled

On Wednesday, 187 arriving flights and 227 departing flights were cancelled at Pearson International Airport.

Airport representatives are warning passengers to check the status of their flights in advance, and expect delays.

School closures

Wednesday's late-season storm resulted in a number of closures.

  • Durham College: All classes at Durham College and University of Ontario (UOIT) were cancelled. Although classes were cancelled, the college and university remained open.
     
  • Seneca College: Both day and evening classes were cancelled but the King and Newnham campuses’ child care centres remained open.
     
  • York University: All operations at the Keele and Glendon campuses were temporarily suspended after 2:30 p.m. Both day and evening classes were cancelled.
     
  • OCAD University: All classes (including continuing studies) starting at 4 p.m. or later on Wednesday were cancelled. All planned public events continued as scheduled.
     
  • Humber College: Full-time, continuing education and online classes were cancelled. The college's child-care centres remained open until parents were able to pick up their children.
     
  • Sheridan College: Classes on all the college's campuses were cancelled.
     
  • Georgian College: The college's Orangeville Campus was closed. All afternoon and evening classes were cancelled.
     
  • Peel District School Board: All offices and centres were closed at 3 p.m.
     
  • University of Toronto: The schools` Mississauga Campus was closed but both the St. George and Scarborough campuses remained open.
     
  • Centennial College: All full-time and continuing education classes were cancelled. The school`s child care centre remained open.

With files from Fan-Yee Suen, Kendra Mangione and Mariam Matti