Thousands of homes and buildings remain without power across Central and Eastern Canada, as crews continue to work to restore service after an ice storm that threatens to leave people in the dark over Christmas.

The number of outages were down significantly from Monday evening, but the outages still stretched from southwestern Ontario to New Brunswick as of Tuesday afternoon.

The worst-hit area was still Toronto. Mayor Rob Ford – who has not yet spoken to Ontario Premier Kathleen Wynne during the storm - tried to reassure residents without electricity in the middle of a cold snap that crews were working around the clock and that power would be restored for Boxing Day or the day after.

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As of Wednesday morning, about 70,000 Toronto Hydro customers were still without power, the majority being in North York and Scarborough. A Toronto Hydro spokesperson said crews still haven't started on localized outages, which affect individual houses, and fixing those could be time-consuming.

Hydro One said under 50,000 customers across Ontario were still without power Tuesday evening.

Those without power could spend Christmas in the dark amid an extreme cold weather alert issued by the city.

"I would like to say this will be done tomorrow - that's not going to happen, folks. We're going to aim and do our very best for Thursday or Friday," Mr. Ford said.

"I wish I could give you better news, but we are going in the right direction…."

Service resumed on the Sheppard subway Tuesday evening. The five-stop line was suspended for nearly three days after the ice storm hit the city.

Hydro crews from Ottawa and Windsor have arrived and will be assisting local restoration efforts, while crews from Manitoba and Michigan are likely to arrive tomorrow, Mr. Ford said. He added that restoring power to the last 50,000 customers would be the most challenging because it involves "one-offs," or individuals houses on a street where there is power.

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"You don't simply re-energize a feeder [power line] where you may see 1,000 or 2,000 customers come on. You're now into individual homes that you're restoring, so that effort – as you can imagine – is much more time-consuming and labour-intensive," Toronto Hydro CEO Anthony Haines said at a news conference Tuesday.

After recent revelations about Mr. Ford's drug use and behaviour, Toronto city council voted to strip him of certain powers and hand them to deputy mayor Norm Kelly. It has raised questions about who is running the show for the city's storm response.

Mr. Kelly stood behind Mr. Ford throughout a news conference Tuesday morning, but did not answer any questions. It has been reported that Mr. Ford had not been communicating with his deputy mayor throughout the storm's relief efforts, while Ms. Wynne said Tuesday she and her office were dealing with Mr. Kelly and his office. She reached out to Mr. Kelly rather than Mr. Ford, who she has not yet spoken with since the storm hit.

"I have said consistently that we are dealing with the decision makers at City Hall," she said, stressing the controversy around Mr. Ford hasn't impacted the response, nor has his decision to not declare a state of emergency impacted what resources the province is providing.

"Whatever the politics are at City Hall really should have, and has had, no bearing on the province's ability to work with officials in the city," Ms. Wynne said, stressing she was dealing with "on-the-ground, operational decision makers."

Ontario's Ministry of Health and Long Term care has deployed its emergency operations centre to help Toronto hospitals deal with the impact of the storm.

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In particular, Ms. Wynne said, an emergency medical assistance team been sent to Sunnybrook Hospital, and is providing more doctors, nurses and 30 additional beds.

Barney Owens, of Ontario's Office of the Fire Marshall and Emergency Management, said the province's emergency operations has been working with ministries -- including the Ministry of Natural Resources, Ministry of Government Services, Ministry of Transportation and Ministry of Health -- to support the affected municipalities.

In terms of helping people most in need, such as senior citizens, Mr. Owens said municipalities, with help from organizations like the Canadian Red Cross and Toronto Community Housing, are responsible for knocking on doors to check on residents. If assistance is required, "I think we have some members lined up from other organizations that can assist as well," he said.

Toronto Community Housing Corporation said that every resident living in community housing should have received at least one knock at their doors by now, said Toronto Community Housing Corporation spokesperson Brayden Akers. He added that the TCHC is also providing hot meals to residents who need them and facilitating transportation for those trying to get to the city's warming and reception centres.

"Those who require medical assistance -- certain residents may have dialysis treatments or receive oxygen -- we're connecting them with the Community Care Access Centre to make sure that they continue to receive medical care during this time," he said.

A spokesperson from the Red Cross said, at this point, volunteers from their organization have not made door-to-door visits.

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According to John Gosgnach, a City of Toronto communications manager, seniors are being asked to "reach out to their usual sources of support and transportation, whether that be TTC, Wheel-Trans, family and friends or other community resources. Of course in an emergency, 911 should be called."

As of Tuesday afternoon, Hydro One, serving most of the rest of Southern Ontario, had 50,000 customers without power, while PowerStream, serving communities just outside Toronto, had roughly 14,000 without power. New Brunswick had 40,000 without power, Hydro Quebec had 22,000 customers without power and Nova Scotia Power had 1,500 without power.

Crews in New Brunswick were now warning the outage will last until the weekend, as ice-laden trees and branches continued to knock down lines.

The weekend ice storm may also have contributed to the deaths of two people from carbon monoxide poisoning in the town of Newcastle, Ont., east of Toronto. Police in Quebec said carbon monoxide poisoning is believed to be the cause of three deaths in a chalet on the province's North Shore.

Toronto Police said a 52-year-old man and his 72-year-old mother died Monday afternoon after trying to keep warm with a gas generator. The generator was in an adjoining garage to supply electricity to the house, but the fumes managed to seep inside the home. "My heart's with their friends and family, and I know this is a tremendously difficult time," Ms. Wynne said.

A fire official said that in Toronto alone on Monday night, 11 people were taken to hospital showing signs of carbon monoxide poisoning. Captain David Eckerman says firefighters received 41 calls for carbon monoxide, including one case in which people were using a charcoal barbecue to provide heat.

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"It's vital that everyone heed the warnings of the emergency officials. So do not heat your home with devices that are designed for outdoors use. Particularly barbecues and outdoor generators," the premier said.

In New Brunswick, power crews restored power to 7,000 buildings overnight but saw another 3,000 go offline as weather continued to knock out service. The utility said a majority of the buildings that do not have power will be reconnected by late Tuesday. Others may wait until the weekend.

"There's a lot of incidents, they're in various locations and they're very complicated to deal with. You have a lot of tree branches covered in heavy ice... When the crews get there, it can take them hours and hours to untangle the situation," New Brunswick Power spokeswoman Deborah Nobes said Tuesday morning. The utility has 100 crews on the ground, all scheduled to work through the holidays to reconnect customers.

"It's very complicated. That doesn't make it any easier for customers who are waiting in the dark," Ms. Nobes said. "...We're just asking for their continued patience as we work to resolve the situation."

Ontario's Associate Chief Medical Officer of Health Robin Williams said there's been a surge in visits to emergency rooms, and a "mobile field hospital" has been dispatched to help treat patients at Toronto's Sunnybrook hospital. "If you need to go to emergency departments, yes, go, but only if you need to," Dr. Williams said Tuesday.

After the 1998 ice storm that hit Ontario and Quebec, power companies reinforced their infrastructure, trimmed back trees and struck deals with nearby utilities to prepare for the worst. But the industry has warned that major overhauls of the grid are costly, and would likely boost power rates.

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The economic effect of the storm isn't clear. In a note sent out to clients, CIBC World Markets said the 1998 ice storm led the GDP to drop, only to see it rebound afterward, and that it expected this year's storm to have a "negligible" impact. "We do not view this storm as a major economic event," CIBC said.

With reports from Affan Chowdhry, Kaitlyn McGrath, The Canadian Press, Shawn McCarthy and Rob Carrick