Winter is back as more than 20 centimetres of snow fell in Ottawa and areas of eastern Ontario Wednesday, according to CBC Ottawa climatologist Ian Black, causing numerous traffic delays and crashes.

Environment Canada issued a snowfall warning Wednesday with heavy snow expected to last into the night.

"Snowfall amounts near 15 cm are expected by evening with five additional centimetres likely overnight," the statement read, with snow expected to taper off Thursday morning.

Ice pellets were also mixed with snow during the late morning and into the afternoon in Ottawa, leading to wet and slushy roads and sidewalks.

Driving conditions deteriorated during the day and the drive home has been worse than the drive to work. OC Transpo reported delays of 60 minutes for most of its buses, while most school buses were facing similar delays in the region.

Police were also busy due to a rising number of crashes. Ottawa police reported to more than 80 crashes between 9 a.m. and 5:30 p.m.

Roads closed due to downed power lines

Hawthorne Road was closed between Louiseize and Leitrim roads Wednesday afternoon due to downed power lines. That closure lasted into the evening, police said.

Rideau Street was also closed for a short time between Friel and Nelson streets after 7 p.m. but reopened soon after.

Snow rapidly accumulated on untreated roads and caused low visibility in heavy snow. The city imposed an overnight parking ban on Ottawa city streets due to the expected snowfall.

There was a long list of delays and cancellations at the Ottawa airport, as well, and passengers were advised to check the flight schedule ahead of time.

The storm system first moved through the United States Tuesday.