Five days after a winter storm swept through Quebec, more than 21,000 Hydro-Quebec customers are still without power.

However, the Crown corporation said earlier this week that the majority of households without power since the Dec. 23 storm will get their electricity back by Wednesday.

As for the rest of Quebecers who are still in the dark, the head of Hydro-Quebec said she could not provide an exact timeline for when power would be restored to everyone since several outages are in remote locations and comprise a small number of customers at a time.

CEO Sophie Brochu said crews will be out restoring power "surgically" in more complex areas, sometimes using snowmobiles and snowshoes to finish their work.

Of the 1,100 outages on Wednesday morning, the regions with the highest number of customers without power remain the Quebec City area, Saguenay-Lac-Saint-Jean, and Côte-Nord.

At some point or another over the last several days, more than 670,000 customers were without power, according to Brochu. At the worst of the storm, more than 380,000 customers had no electricity at the same time.

SPIKE IN CALLS ABOUT CARBON MONOXIDE POISONING

As people are desperate to heat their homes, the Quebec City fire service warned residents over the Christmas weekend to use caution after noticing a spike in calls about carbon monoxide poisoning.

Alexandre Lajoie, a fire service spokesperson, said they have received at least 10 calls about CO poisoning since last Thursday related to heating appliances that use propane.

"What we're asking people to do is simply to make sure that they're using heaters [indoors] that are made for it," Lajoie said in an interview Tuesday. 

"So they need to follow the manufacturer's recommendations. The most important [thing] is to have a carbon monoxide alarm because without it, you cannot know it's really there."

Residents are urged to use battery-powered CO detectors to be warned about the gas, known as a silent killer since it has no odour and can go undetected. 

Symptoms of intoxication include nausea, headache, fatigue, vomiting, and loss of consciousness.

Inhaling carbon monoxide can be deadly depending on the concentration in the air and the amount of time someone has been exposed to it.

Lajoie also said residents should check that their smoke alarms are functional as well after one fatality on Saturday was reported during the storm due to a fire believed to have been started by a burning candle.