A winter storm is spoiling travels plans and causing power outages as parts of southern Ontario dig out from under heavy snowfall.

Hydro One is reporting about 29,000 customers in southwestern Ontario are without power in the aftermath of a storm that brought a mix of freezing rain, snow and ice pellets.

Buses are cancelled at number of school boards, including in Ottawa and across the Greater Toronto and Hamilton Area.

More than 100 flights in and out of Toronto’s Pearson International Airport are cancelled after the storm dumped about 17 centimetres of snow on the city.

Environment Canada says southern and southwestern Ontario could see periods of freezing drizzle and icy conditions into the afternoon.

The agency says parts of eastern Ontario could see an additional two to four centimetres of snow Thursday morning, with another round of snowfall possible in the afternoon and evening.