An Arctic cyclone that hit much of the United States on Saturday left more than 700,000 people without power, with at least 16 people killed in weather-related car accidents and thousands stranded by flight cancellations, Reuters reported.

Many electric companies continued to ask customers to conserve energy. Duke Energy (DUK.N) told customers by Saturday evening that it had ended the 15- to 30-minute power outages in North and South Carolina that it had initiated earlier in the day.

Flight tracking service FlightAware said more than 2,700 U.S. flights were canceled Saturday, and the total number of delays exceeded 6,400.

The American Automobile Association estimates that 112.7 million people will travel 80 miles or more from home between Dec. 23 and Jan. 2. But stormy weather approaching the weekend likely caused many people to stay home.

At least 16 people were killed in weather-related car accidents across the country, and hundreds were stranded on icy and snow-covered roads, according to media reports.

In Erie County, upstate New York, about 500 motorists were stuck in their cars from Friday night to Saturday morning. At least one person was found dead in his car.