Toronto Hydro reports this morning that less than 150,000 customers are still waiting for power — down from a peak of more than 300,000.
In a tweet early this morning, the utility said now that critical customers have been addressed, they are working to fix feeder lines to restore power to large numbers of customers.
However, officials with the utility said Monday many customers could be without power until the weekend.
"While we're making progress, restoration for all customers could take a few more days," Toronto Hydro tweeted. "Please make alternate arrangements if you can."
Hydro One says about 56,000 of its customers outside of Toronto remain in the dark, and PowerStream, which serves areas north of Toronto, has about 6,400 clients awaiting power.
Premier Kathleen Wynne said the progress in affected areas is promising, but acknowledged the continued outages are a concern.
"My concern is people living in high-rise buildings who can't get down and who may have issues getting water," Wynne told CBC News.
“That has been a very prime focus with the city of Toronto, particularly because of the volume of high-rise buildings, and so we continue to work and provide whatever services the City of Toronto needs, and have done from the beginning."
In Quebec, fewer than 33,000 customers remained without power as of early Tuesday, largely in the province's Eastern Townships as technicians worked to fix electricity lines and other equipment damaged by the storm.
The power outages combined with the sharp drop in temperatures have left some residents resorting to dangerous measures to stave off the cold.
Two people were killed in Newcastle, Ont., after carbon monoxide seeped into their home from a gas generator running in the garage. Police say the generator was being used to help heat the house.
Emergency crews in Toronto have responded to about half a dozen calls because of exposure to carbon monoxide. Officials say people are burning charcoal in their homes in an attempt to stay warm.
Light snow in the forecast
Special weather statements are in place in much of southern Ontario as temperatures drop.
"With so many still out of power there is real concern due to the cold temperatures behind the ice storm," said CBC meteorologist Colette Kennedy.
"For the Greater Toronto Area and southern Ontario, flurries today but we will add some light snow from a weak system that will move in into Wednesday. So, yes, a white Christmas is possible with just a dusting … but the weight of even some light snow will not help weak, ice-covered branches and power lines."
Environment Canada says temperatures are expected to remain "well below freezing" through to Christmas Day.
"To those who are still without power due to continued challenges in getting the hydro lines up and running it is advised to seek warm shelter and prepare for the colder than average temperatures that are expected," the forecast advises.
"Furthermore, given the well below freezing temperatures, much of the ice will not melt and will likely remain on many surfaces through Christmas and Boxing Day until the end of the week."
The Greater Toronto Area bore the brunt of the storm on Sunday with between 10 and 30 millimetres of ice accumulation bringing down tree limbs and power lines.
Power outages in the Maritimes
Meanwhile, an icy mix of rain and freezing rain played havoc with the electricity grid across the Maritimes on Monday.
Ice-laden trees fell on power lines, leaving tens of thousands of homes and businesses in the dark in southern New Brunswick and northern Nova Scotia.
N.B. Power said about 49,000 customers were without power in southern New Brunswick early today.
The hardest hit communities were Rothesay and St. Stephen, where about 28,000 customers were in the dark.
N.B. Power spokeswoman Deborah Nobes said the number of outages rose through the day due to a growing number of downed lines in the Fredericton and Moncton areas as temperatures rose.
Nobes also said icy roads were making it difficult for N.B. Power trucks to get to problem areas.
In Nova Scotia, NS Power said almost 10,000 customers were without electricity by early evening, but that number had dropped to about 6,600 by early today.
Most outages are in the Annapolis Valley from Windsor to Kentville.
"[The Maritimes are] still dealing with the remnants of the storm which has given a few day's worth of snow, freezing rain and drizzle in some locals," Kennedy said.
"Today Nova Scotia will see a rain/snow mix with up to five centimetres. Flurries for P.E.I. and New Brunswick. However, tomorrow another system skirts by and Nova Scotia may pick up another two to four centimetres of snow with a light dusting possible in southern New Brunswick."
Meanwhile, travel was disrupted across the Maritimes due to slick roads, while dozens of flights were delayed or cancelled at airports — mainly due to backlogs created by severe weather that also hit Quebec and Ontario.
Environment Canada has forecast colder temperatures for Central Canada over the next several days, meaning the ice is likely here to stay for some time. Commuters are warned that untreated roads may be slippery, making travel difficult.
Passengers were stranded in airports from Toronto to St. John's. Several airlines, including Air Canada, advised passengers to check their flight status before heading to the airport. They also urged passengers to give themselves extra time in case of delays on the road.