New York Waterway ferries move as ice floats on the Hudson River seen from the Edge sky deck at Hudson Yards, Tuesday, in New York. (AP Photo/Yuki Iwamura)

Three Texas siblings who perished in an icy pond were among several dozen deaths in U.S. states gripped by frigid cold Tuesday as crews scrambled to repair hundreds of thousands of power outages in the shivering South and forecasters warned the winter weather is expected to get worse.

Brutal cold lingered in the wake of a massive storm that dumped deep snow across more than 1,300 miles from Arkansas to New England and left parts of the South coated in treacherous ice.

Freezing temperatures hovered Tuesday as far south as Tennessee, Arkansas and North Carolina, and were forecast to plunge again overnight. Parts of northern Florida were expected to sink to 25 F late Tuesday into early today.

The U.S. aviation system was returning to normal after a brutal weekend that saw more than 17,000 commercial flights canceled. There were about 6,300 cancellations in the U.S. Monday and about 2,500 Tuesday, according to FlightAware, a flight tracking and data company. Less than 500 were anticipated to be canceled Wednesday.

The arctic misery over the eastern half of the U.S. was expected to worsen Friday and Saturday. The National Weather Service said another winter storm could hit parts of the East Coast this weekend, and more record lows were forecast as far south as Florida.

“This could be the coldest temperature seen in several years for some places and the longest duration of cold in several decades,” the agency’s Weather Prediction Center warned Tuesday.

Officials in states afflicted with severe cold reported at least 45 deaths.

Three brothers ages 6, 8 and 9 died Monday after falling through ice on a private pond near Bonham, Texas, Fannin County Sheriff Cody Shook said Tuesday. The boys’ mother said she ran into the freezing lake and frantically tried to pull her sons from the water, but the ice kept breaking beneath them.

“They were just screaming, telling me to help them,” Cheyenne Hangaman told The Associated Press. “And I watched all of them struggle, struggle to stay above the water. I watched all of them fight.”

More than 410,000 homes and businesses remained without power Tuesday evening, with over half the outages in Tennessee and Mississippi. Reconnecting some hard-hit areas could take days. Electric utility Entergy said some of its 6,000 customers in Grenada, Mississippi, might not have power until Sunday.

Jean Kirkland used a lighter and paper Tuesday to ignite her gas stovetop. Her neighborhood in Lexington, Mississippi, lost power Sunday, and Kirkland and her daughter have been relying on the stove and a couple of gas-powered heaters to keep warm. Outside, icicles dangling from power lines clattered.

“When you’re used to certain things, you miss them when they’re gone,” said Kirkland, who’s been getting by without hot water and lights at night.

Health officials warn against using gas-powered stoves to heat a home. They can give off fumes that increase the risk of carbon monoxide poisoning, according to the U.S. Centers for Disease Control and Prevention. At least one carbon monoxide death was reported in Louisiana, according to the state Health Department.

Dozens of Mississippi counties were in need of bottled water, blankets, tarps, fuel and generators, and the Federal Emergency Management Agency was sending trucks loaded with supplies, Gov. Tate Reeves said Tuesday.

In New York City, officials said 10 people had been found dead outdoors in the cold. More deaths were reported across a dozen states. They included two people hit by snowplows in Massachusetts and Ohio, two teenagers killed while sledding in Arkansas and Texas, and a man found in his home in the Indianapolis area with no heat.