An overnight snowfall Thursday night into Friday morning led to a messy day on the roads.

By 6 p.m. Friday, Ottawa Police said they had responded to a total of 102 crashes. 21 collisions occured between midnight and 8 a.m. Friday, most of them were vehicles sliding into ditches, police said.

About eight centimetres of snow fell before 7 a.m. at the Ottawa Airport, with another five centimetres expected throughout the day, according to Environment Canada.

Environment Canada says Ottawa will see about another half-dozen snowstorms this season.

The City Of Ottawa has been monitoring the roads since Thursday evening.

"We've salted, we've plowed," said Luc Gagne, the Manager of Roads Services for the City of Ottawa.

"Our arterial road network is in fairly good condition"

Meanwhile, Ottawa Police are encouraging drivers to prepare their vehicles for winter.

"It's not mandatory in Ontario to have snow tires, but snow tires are a good idea," said Sgt. Mark Gatien.

"We do recommend you put snow tires on, but snow tires do not mean you can drive like it is summer time."

School buses were cancelled for the Ottawa Carleton District School Board, Ottawa Catholic School Board and others. Schools remain open. For a full list of school bus cancellations, visit this page.