The weather system that hit on the weekend downed power lines, splintered trees and caused wide-spread travel delays.
Hydro crews have been working around the clock to restore power to homes which have now been in the dark for three full days, but utility companies said some might have to wait until the weekend to get their lights back on.
In Toronto — where some 300,000 customers were without power at the height of the storm — about 69,000 customers remained without electricity on Christmas Day.
Toronto Mayor Rob Ford said it "has been a very challenging four days," but the city is doing its best through the holidays to restore power to all homes as soon as possible.
Authorities have been urging those in homes with no power to make alternative arrangements for the holidays and to take advantage of warming centres being offered in many communities.
Ford said some 1,000 people sought refuge at the warming spots in Toronto on Tuesday night.
"That's the highest number we've had. It's gone from 500, to 750, to 1,000," Ford said.
"Hopefully that number will go down as the hydro is restored, but we're expecting more people tonight."
Toronto Hydro CEO Anthony Haines said the "best guess" for reconnecting remaining customers is Friday, but he cautioned that could easily change depending on available resources and the amount of felled tree branches and lines to repair.
Environment Canada is warning that gusts of wind could hit Toronto and much of southern Ontario Wednesday afternoon.
The weather agency said the winds, while forecast to be relatively minor in strength, could potentially bring down more icy tree branches.
Without power since early Saturday, east-end Toronto resident Deborah Coombs along with her husband and seven-year-old son finally left their freezing home on Tuesday for the comfort of a hotel room. They managed to bring along a small Christmas tree, which they tucked their gifts under.
"We're making the most of it. We're family and we're together and now we have a warm roof over our heads," she said, adding she intends to cook the turkey left behind in her fridge if it's still edible when power returns.
However, she said the dozen or so fish in their large tank perished as temperatures at their house in the part of the city with the most outages dipped to 5 degrees.
"So now we have Christmas outside our house but we also have to explain to our son that all of our fish are gone," Coombs said. "I'm not sure when to tell him."
Officials have also warned people about the deadly risk of carbon monoxide poisoning as some residents are reported to have used equipment designed for outdoor use — like gas powered generators, charcoal stoves and barbecues — inside their homes.
Toronto Fire Chief Jim Sales said authorities received 302 suspected carbon monoxide calls since the storm hit. The fire department typically gets about 20 such calls a day.
Two children and two adults in east-end Toronto were taken to hospital to be treated for carbon monoxide poisoning Wednesday morning after using a charcoal barbecue indoors.
And two people died of carbon monoxide poisoning in Newcastle, Ont., east of Toronto, on Monday after trying to keep warm with a gas generator in a garage.
Meanwhile, Hydro One, which serves 1.3 million customers in Ontario, had about 15,000 customers still without power, including about 6.200 in Guelph and 4,100 in Orangeville.
Power Stream, which serves Markham, Richmond Hill and Vaughan, said about 3,600 customers in those cities were still without hydro. And Veridian Connections, which serves the Pickering and Ajax areas east of Toronto, said about 1,700 customers were still affected.
In Quebec, some 8,400 customers were without electricity, primarily in the Eastern Townships.
In New Brunswick, 18,600 customers were still in the dark, including about 11,000 in the Rothesay area north of Saint John.
NB Power spokeswoman Deborah Nobes said people who had been without power the longest were the priority.
"We're trying to get to those people because it is getting a bit cold out," said Nobes. "(We're) also focusing efforts on incidents that have the most customers attached to them."
Nobes said the utility hopes most people will have power by Saturday, but others may have to wait longer.
There was good news in Nova Scotia though, where all power to affected customers had been restored by Christmas Day.
— with files from Aly Thomson in Halifax.
Also on HuffPost