The season's first snowfall led to dozens of crashes and delays for commuters in eastern Ontario on Wednesday morning, and residents are urged to prepare for heavier snow over the next 24 hours.

Wednesday's snow wasn't deep enough to cover the toes of most people's boots and it quickly began melting into slush.

Even so, there were over 40 crashes in Ontario east of Napanee by 9 a.m., and Highway 417 was particularly bad, reported provincial police Const. Kevin Davidson.

"We have vehicles driving too fast, going into ditches, off the shoulders, colliding with other ones at intersections, rear-enders — the whole gamut of people trying to rush and hurry when they should be taking their time," he said.

"It always seems to be this way, that people have to rethink winter driving over again every start of every new year."

To make things worse, Davidson said, at this time of year some counties don't yet have their snowplows ready or winter staffing levels to operate them.

Fortunately, he said, there were very few injuries — just thousands of dollars in property damage.

15 cm of snow in Thursday's forecast

Environment Canada forecast periods of heavy snow in the Ottawa area starting Wednesday evening, with around five centimetres overnight. Another 15 cm was expected on Thursday, when the temperature is forecast to stay below -4C.

Ottawa residents awoke to the season's first snow Wednesday.
(CBC)

Dan O'Keefe, manager of road maintenance for City of Ottawa, said 120 plows and salt trucks began working early Wednesday morning and were to be out again overnight.

Nevertheless, he expected traffic delays again Thursday morning.

"Everyone should take their time and give themselves lots of room between the vehicle in front of them," he said.

In preparation for the snow-clearing work, the city has banned parking on city streets between 1 a.m. and 7 a.m. Wednesday night, and will be ticketing violators.