Tens of thousands without power this Boxing Day in Canada and US

Authorities warn of carbon monoxide poisoning as two die after using gas generator in storm

A lineman works on connecting fallen wires in Michigan

Tens of thousands of households are still without power on Boxing Day in Canada and could remain this way until the end of the week, officials have warned.

About 69,800 Toronto customers are without power, 21,000 are still without power in Quebec and 21,000 do not have electricity in New Brunswick, according to CBC news. In the US, More than 200,000 properties in Michigan and Maine were still cut off yesterday evening and forecasters have warned the situation could worsen as a second bout of snow is predicted.

Repair crews worked through the day and night on Christmas Eve and Christmas Day to restore power to nearly half a million people in parts of the central and northeastern United States and into eastern Canada following a weekend ice storm that at least 27 deaths have been linked to.

The US National Weather Service said more snow was expected to move into the Northern High Plains and Central Rockies on Tuesday before rolling into the Great Lakes and Midwest by Wednesday morning. Some US states were keeping emergency shelters open for those still stuck power.

In Canada, Toronto also opened warming shelters for people without power and some residents were warned they may not have electricity back until the weekend.

Five people were reported to have died from apparent carbon monoxide poisoning. Police said two people in Ontario died after using a gas generator situated in their garage to heat their home following a power-cut in northeast of Toronto. The victims were a 52-year-old man and his 72-year-old mother, CBC news reported.

Police in Quebec said they believed carbon monoxide poisoning to be the cause of three deaths in a chalet on the province's North Shore. Earlier in the day, five people were killed in eastern Canada in highway crashes blamed on severe weather conditions.

In the US, the nationwide death toll from the storm reached at least 14 on Tuesday, when a 50-year-old man in Knox, Maine, was overcome by carbon monoxide fumes from a generator. It was the second reported death attributed to fumes from a generator during the storm. Police in Michigan confirmed two people died in a traffic collision on Monday during the storm.

Ninety thousand customers remained without power on Tuesday as temperatures plunged to -15c in Toronto. Authorities responded to 110 calls in a 24-hour period.

"We're looking at approximately six times as many calls," Toronto Mayor Rob Ford said during a news conference on Tuesday, describing the storm as one of the worst in the city's history. "I understand they want to keep warm but you cannot do this. This is deadly."

EMS Deputy Commander David Vijakainen warned residents not to use any appliances that burn inside a home, and cautioned against using multiple candles to light a home. "Basically the warning is simple: Do not burn charcoal or propane in enclosed space," he told CBS News.

In Toronto, where 300,000 customers lost power at the height of the storm, crews from Ottawa, Windsor, Manitoba and Michigan were helping local teams with their efforts.

Elsewhere in Ontario, more than 52,000 customers remained without power on Tuesday, along with 31,700 customers In Quebec who were still without power as of Tuesday morning. In New Brunswick, more than 40,000 customers were stuck in the dark, and about 2,000 were without power in Nova Scotia.

Canadian utility officials warned that some customers could be without power until Saturday.

The number of customers in Maine without power spiked to more than 100,000 on Tuesday, even as Central Maine Power Co. sent more than 1,000 workers to help restore power throughout the state.

This was also the case in Michigan, where Jackson-based Consumers Energy — the state's largest utility — said it hadn't had this many outages during any Christmas week since its founding 126 years ago. Almost 17 percent of its 1.8 million electric customers lost power during the storm that hit late Saturday; roughly 152,000 remained without it Tuesday.

Additional reporting by Associated Press