Mayor Naheed Nenshi provided an update Sunday morning in Calgary, saying Enmax has told him it could be four to seven days before power is restored to several thousand people downtown.
Enmax says there are 1,900 sites with metres in 112 buildings that are without power.
Power was shut down to the area around Eighth Street S.W. and Fifth Avenue as a safety precaution, Enmax says.
As well, Nenshi says residents without power are being advised to unplug all electrical appliances and stoves to prepare for a power surge when their section of the grid is re-energized.
The cause of the fire is still under investigation and Enmax says it is too early to estimate cost of damages.
However, Nenshi urged Calgarians to reach out to affected friends and family to provide Thanksgiving dinner and a place to stay.