The lights are back on in the city after the effects of post-tropical storm Sandy knocked out the power to tens of thousands in Toronto.

The superstorm brought strong winds and heavy rain to southern Ontario, Quebec and parts of the Maritimes. At the height of the storm, nearly 150,000 Ontarians were without power.

Toronto Hydro is reporting that, as of Wednesday morning, power has been restored to 99 per cent of its customers, while approximately 600 remain in the dark.

The company is asking customers who remain without power to contact Toronto Hydro, even if they have previously reported the outage.

More than 85 per cent of the outages were caused by trees and branches falling into powerlines, poles and transformers – a consequence of the wind gusts that reached 90 km/h in the city.

The cost of many repairs needed could reach $1 million, Toronto Hydro reports.

“Localized outages affecting one or several houses at a time are being attended to by powerline crews,” reads a statement from Toronto Hydro. “However, they are scattered across the city in relatively small pockets, which means that it will take time to reach all remaining customers.”

The company said it expects to have power restored to most customers by the end of the day, however, it warned that some small outages could last through to Thursday.

Hydro One, which delivers power to the largest geographical region in Ontario, saw power to more than 90,000 customers knocked out. As of Wednesday afternoon, the company reported that power was restored to all but 6,000 customers. The company expects most of the power to be restored by 6 p.m..

Other Ontario communities still facing outages include Peterborough, Parry Sound, Bracebridge, Algoma, Kent and Lambton. The high winds also knocked out power to 50,000 in Quebec and 14,000 in Nova Scotia.

All of Toronto public schools reopened Wednesday, with the exception of James Cardinal McGuigan Catholic Secondary School in the Finch Avenue and Keele Street area, which remains without power.

The high winds are also being blamed for the death of a woman in Toronto, who was killed after debris from a Staples sign came loose and struck her close to St. Clair Avenue West and Keele Street.

The massive storm system travelled north after barrelling through the northeastern United States, where it caused flooding, widespread power outages and at least 50 deaths.