Montreal is among the worst affected by the power outages after Wednesday's ice storm
More than 1.2 million people were without power in Canada's two most populated provinces, Ontario and Quebec, on Thursday morning a day after freezing rain and strong winds hit the southeast of the country, toppling trees onto power lines.
There were 1,000 workers trying to restore power overnight and Thursday morning in Quebec, the province's electricity provider said, warning that more outages could still occur.
"We are confident that we can restore power to some of the affected customers today," Hydro-Quebec said in a statement. "Unfortunately, it is already expected that some customers will still be without power on Friday and this weekend."
About 1.1 million people did not have power in Quebec and about 167,000 in Ontario as of 10:35 am (1435 GMT), according to Poweroutage.com. Ontario and Quebec account for more than half of Canada's total population of about 39.6 million.
In Ottawa, crews were expected to restore power for a large portion of some 65,000 affected customers by noon, mayor Mark Sutcliffe said.
Some areas in the national capital "remain hazardous due to fallen debris and power outages affecting traffic signals," he said.
Canadian Prime Minister Justin Trudeau, who was scheduled to be in Montreal on Thursday to speak about his government's budget, offered to provide federal assistance if required.
Montreal is among the worst affected by the power outages after Wednesday's ice storm, according to Hydro-Quebec.
"We're thinking of everyone in Quebec and Eastern Ontario affected by yesterday's storm - and we're thanking the crews who are clearing roads and restoring power," Trudeau said on Twitter.