I imagine the weather in Toronto was similar to Waterloo yesterday (since Waterloo is ~ an hour away on the 401.) School buses were cancelled in Waterloo yesterday because there was freezing rain overnight followed by snow in the morning that continued into the afternoon. So lots of ice covered by snow. It was tricky walking in to the University without cracking my head open due to snow covered ice, so if it was similar in Toronto I think the article is downplaying what the weather was like.
Where is the article "'Wimpy' School buses in Kitchener-Waterloo cancelled due to a Teeny Bit of Snow"?
Edited to add another Toronto Star article from Yesterday:
http://www.thestar.com/News/GTA/article/278872
So, freezing rain followed by 5-10 cm of snow.. Police are worried about accidents, road conditions..