(NewsNation) — Colder temperatures from a huge winter storm and higher usage of heat led Duke Energy to intentionally cut off power for rolling blackouts Saturday.

More than 450,000 were without power in North Carolina on Christmas Eve morning, as the storm, which is creating high winds, frigid temperatures and dangerous wind chills, continues in much of the U.S. That number later went down to a little over 200,000 in the afternoon, according to a website that tracks outages.

At least 12 deaths have been blamed on the storm, including two in a Buffalo suburb after emergency crews couldn’t get to their homes when they suffered medical emergencies.

Outages started affecting people at around 9:29 a.m., NewsNation local affiliate FOX8 reported. According to the Charlotte Observer, these rolling outages, which were supposed to be around 15-30 minutes long across North Carolina, stopped at about 11:30 a.m.

Duke Energy spokesman Bill Norton said to the newspaper, though, that he does not know how long it will take to restore power to everyone.

Gov. Roy Cooper spoke to Duke Energy CEO Lynn Good Saturday morning to offer assistance and “express urgency” about the need to restore power quickly, he posted on Twitter.

“Grateful for the workers braving the wind and cold to get the power back on,” Cooper wrote.

Duke Energy in a statement said that as extreme temperatures drive “unusually high energy demand across the Carolinas,” it was necessary to perform the temporary outages “to protect the energy grid against longer, more widespread outages.”

“Extreme cold weather is creating unprecedented demand on the system. We’re restoring customers impacted by emergency temporary outages and remaining storm outages,” the company said in a later tweet. “Please continue to conserve electricity without sacrificing safety. Your support can help keep power on for all.”

Some ways Duke Energy suggested conserving electricity in a press release are:

• Lower your thermostat if you can safely do so
• Set your water heater to 120 degrees or less.
• Limit the use of your washer, dryer and dishwasher, or if you must run them, do full loads.
• Unplug standing appliances, as ones left plugged in use up energy
• Turn off lights when leaving a room.

Duke Energy’s Jeff Brooks told FOX8 that the temporary outages are not expected to affect Christmas Day.

The Associated Press and NewsNation local affiliate FOX8 contributed to this report.