There was another power failure in Newfoundland Sunday night, a setback for residents trying to deal with rolling blackouts and the aftermath of a blizzard.  

Newfoundland Power said about 90,000 customers had lost power after the Holyrood power plant stopped generating electricity due to a sudden problem. Some customers were being reconnected late Sunday night.  

The utility said there had been a flash at the hydro plant's switchyard, with residents reporting hearing a bang. Newfoundland and Labrador Hydro said officials are trying to determine what happened at the plant. A spokesperson said there were no injuries.

The outage came after the province entered its third day of rolling blackouts, with residents and large consumers being told to conserve energy -- which could include reducing or stopping operations over the next few days, in order to get through a "critical period," Premier Kathy Dunderdale said Sunday.

"We need to become more mindful of energy conservation and we really need to focus on that over the next few days and the next number of weeks," she said during a press conference in St. John's.

A fire at a terminal Saturday morning knocked out power for 190,000 customers, mostly in eastern parts of Newfoundland. Since then, progress to restore power has been made, but some homes and businesses could be in the dark until Tuesday.

Rotating blackouts were implemented by the utility last week as it tried to handle increased demand because of frigid temperatures.

Dunderdale says those factors, combined with a blizzard that ripped through the region overnight Friday, have caused demand for energy to increase significantly.

Ontario, Quebec see freezing rain

Meanwhile, other parts of the country were bracing for some harsh winter weather Sunday night and overnight.

Snowfall and freezing rain hit southern Ontario Sunday evening during the province’s first winter storm of 2014.

Environment Canada had issued freezing rain and snowfall warnings for the entire southern part of the province, as a weather system intensifying in the U.S. makes its way north.

Upto 25 centimetres of snow were forecast in areas north of Toronto, stretching from Pembroke in the east to Leamington in the west.

Closer to the Greater Toronto Area, the snow was forecast to change to rain as temperatures rise above the freezing mark. However, as the mercury drops overnight Sunday, prolonged freezing rain is expected, making for a slow, slippery commute Monday morning.

Environment Canada is warning that driving conditions may become more dangerous due to falling and blowing snow. When the freezing rain begins to fall, roads could quickly become icy and slippery.

However, a meteorologist with the agency is assuring Ontarians that the weather conditions won't be anything like the ice storm experienced late last month.

"When you get a crest of freezing rain on snow, it's not that difficult," says Arnold Ashton, an Environment Canada meteorologist. "You're not chipping away at ice for an hour on your car, the roads aren't completely treacherous and glazed because you've got that under-layer of snow."

Ashton told CTV News Channel on Sunday that the accumulation of ice on hydro lines and tree branches isn't expected.

He did warn, however, of bitterly cold temperatures that are expected descend on the GTA Monday and continue through to Wednesday, bringing in some of the coldest temperatures in years.

"It's going to be records smashed," he said. "We're going to see fairly brisk winds and wind chills are going to be very dangerous through that period."

Temperatures in Toronto are expected to fall to -11 C Sunday and drop to a high of -17 C by Tuesday.

Later this week, the mercury should begin to rise with a high of 3 C forecast for Saturday.

"By end of week, above normal temperatures will probably melt some of that snow," Ashton said. "It will feel positively balmy by comparison."

In northern Ontario, up to 15 centimetres of snow is forecast for some areas, while wind chill warnings are in effect with temperatures expected to drop to -35 C.

The same storm system is expected to affect Quebec, as Environment Canada warns up to 20 millimetres of freezing rain is expected to fall Sunday night over the southern and central parts of the province.

The agency says the freezing rain will change into rain Monday morning with milder temperatures coming into the area. However, that's not expected to last long.

"A cold front associated with the storm sweep over these regions making the temperatures fall rapidly Monday afternoon," Environment Canada warns.

Prairies locked into deep freeze

Further west, extremely cold, dense air has encased much of the Prairies.

Wind chill warnings remain in effect for Saskatchewan, Manitoba and parts of northeastern Alberta.

Dangerous wind chills of -50 C greeted residents of Winnipeg and Regina Sunday morning, with the frigid temperatures expected to continue into Monday.

But some relief is in sight, as significant warming is expected across southern Saskatchewan and Manitoba beginning later this week.

With files from The Canadian Press