US weather: Thousands of flights cancelled and more than 810,000 homes without power as huge winter storm hits

More than 810,000 homes are without power and thousands of flights have been cancelled as a huge winter storm hits the US, from the southern Rocky Mountains to New England.

At least 180 million people in 37 states - more than half America's population - are affected, according to the National Weather Service (NWS).

Seventeen states and the District of Columbia have declared an emergency, with rescue teams and supplies on standby.

The number of deaths attributed to the storm now stands at 15, officials said.

There were three fatalities in Pennsylvania, three in Tennessee, two in Louisiana, two in Texas, two in Mississippi, one in Kansas, one in Massachusetts and one in Arkansas, Sky's US partner network NBC News reported.

Temperatures plunged to -20C in Texas, while in New Mexico, residents were deluged by 31 inches (78cm) of snow.

"This storm is exiting the East Coast now, with some lingering snow squalls," said Allison Santorelli, a meteorologist with the NWS's Weather Prediction Centre.

"But the big picture story is the extreme cold, ​it's lasting into early February."

There were widespread power outages across the US, with 813,498 homes without power just before 11am eastern time on Monday (4pm UK time), according to PowerOutage.us.

Tennessee was the worst-hit state with 250,203 outages reported, followed by Mississippi with 160,751 and Louisiana with 126,207.

Josh Weiss, from the National Oceanic and Atmospheric Administration, said the storm was "unique" due to its broad spread - covering 2,000 miles - and the extreme cold it's forecast to bring over the next week.

More than 14,500 flights were cancelled on Sunday and another 5,500 delayed, according to tracking website FlightAware, making it the worst day for flight cancellations in the US since COVID, aviation analytics firm Cirium claimed.

There were more than 6,400 flight delays and cancellations nationwide on Monday, according to flightaware.com.

Homeland Security secretary Kristi Noem urged people to "stay home" due to "very, very cold" temperatures.

Thousands of bin lorries have been fitted with snow ploughs in New York City, said mayor Zohran Mamdani, who warned of the coldest temperatures for eight years.

In Central Park, where some people used skis to get around, 28cm of snow were reported on Monday.

Students in America's biggest city have been told that Monday will be a remote learning day.

Similar orders are in force in other storm-affected states.

"An Arctic siege has taken over our state," said New York governor Kathy Hochul. "It is brutal, it is bone-chilling and it is dangerous."

New York communities near the Canadian border have already seen record-breaking lows, including -45C (-49F) in Copenhagen, a village in Lewis County.

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Mikie Sherrill, the governor of New Jersey, announced a 35mph speed limit on highways and said she was expecting conditions the "likes of which we haven't seen in years".

In Georgia, senior state meteorologist Will Lanxton said it was "perhaps the biggest ice storm we have expected in more than a decade".

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