The power failure began Saturday after a fire in an underground vault sent smoke and blue flames out of a manhole.
Utility provider Enmax said the damage was extensive and completely destroyed electrical infrastructure. About 3.5 kilometres of cable needs to be replaced.
The power outage has left approximately 2,100 businesses and 5,000 residents in the dark, as well as several government buildings, including the Alberta government's McDougall Centre. The building houses the premier's Calgary office and the Calgary Courts Centre.
Despite progress on repairs, officials expect it will take until Thursday for things to return to normal.
"Although the roads are open, it doesn't mean we are done. There's still a lot of work that has to be done to get people back into their homes," said Ken Uzeloc, director of the Calgary Emergency Management Agency.
"We have many residents who are still out and our priority is to make sure that they have a safe place to stay until the power is restored later this week."
Uzeloc said the city provided 350 hotel rooms for those affected Monday night but available space was rapidly running out.
"We're very close to exhausting our room availability at this point and, with that in mind, we have established a lodging centre and are ready to open that if the numbers of people in need accommodations increases again," he said.
Traffic patterns Tuesday morning appeared normal, but many buildings remained without power. The eerie glow of emergency lighting was barely visible in some residential highrises. The dull hum of electrical generators could be heard throughout the downtown.
"Of the 127 high voltage cables that did need to be replaced, 79 of them, which are the most critical, have been pulled in," said Enmax President Gianna Manes.
"Our next steps now are going to be splicing all the new cables back into the grid. Approximately 15 per cent of the critical splices have already been completed, which are required to restore power," she said.
"It's also the most time consuming work that we will do in order to get power restored to this area. But based on the progress we made last night and yesterday, we continue to be on schedule to restore the entire affected area by mid-Thursday."
Uzeloc said Calgarians seem to have become skilled with dealing with emergencies following massive flooding last year and a heavy snowfall in early September that wreaked havoc with about half of the city's trees.
"Calgarians have unfortunately had a lot of examples where they've had the opportunity to go through crises and Calgary has always shown how well we can deal with things," said Uzeloc.
"We don't have the same issues that a lot of other big cities have when we have major events like this."
The cause of the fire has not been determined. There is no time frame on when Enmax will know what happened Saturday.
"This particular type of occurrence is not commonplace, so we don't have any reference points as to how long something like this will take," said Manes.
"The investigation will take as long as the investigation needs to take so that we can arrive at a conclusion for a determination of cause."
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