A huge winter storm sweeping across many states in the US is causing thousands of flights to be delayed or cancelled as residents are gripped by fear of a possible heaviest snowfall in a decade.

Thirty states have been put under a weather alert after a state of emergency was declared in Kentucky, Virginia, Kansas, Arkansas, and Missouri.

A blast of snow, ice, wind, and plunging temperatures stirred up dangerous travel conditions in the central US on Sunday, blanketing major roadways.

CNN reports that as many as 62 million residents are to be affected when the storm unleashes a barrage of heavy snow, treacherous ice, rain, and severe thunderstorms across a 1,300-mile (2092.1472 kilometres) swath of the US.

“For locations in this region that receive the highest snow totals, it may be the heaviest snowfall in at least a decade,” the National Weather Service said.

Forecasters say the extreme weather is caused by the polar vortex—an area of cold air circling the Arctic.

Usually, the polar vortex stays up around the North Pole, but it can shift and expand, bringing lower temperatures further south than usual.

The polar vortex had been expanding over the US in recent days before the winter storm began to hit on Saturday evening.

The weather service warned that severe thunderstorms with the possibility of tornadoes and hail may occur in some regions over the next few days.

Meanwhile, in the United Kingdom (UK), some airports in Manchester, Liverpool, and Birmingham closed off runways after a heavy snowstorm swept through the city.

The UK’s national grid and operators reported power outages across homes in the country.

China is facing a spike in the outbreak of a new strand of infectious respiratory virus.

The virus, identified as human metapneumovirus (HMPV), is a single-stranded ribonucleic acid (RNA) virus that causes symptoms similar to the common cold and influenza.

HMPV, which comes with severe complications like pneumonia in infants, elderly, and those with weakened immune systems, spreads through respiratory droplets or contact with contaminated surfaces.

Its symptoms include cough, fever, nasal congestion, and fatigue, with an incubation period of three to six days.

The virus was first reported in 2001 in The Netherlands, and has since surged across northern Chinese provinces during the winter season.

This comes barely five years after the world saw the spread of the deadly COVID-19 virus which killed nearly seven million people globally.

Hospitals in China are experiencing rise in patients with symptoms of the virus, as health authorities in the country are implementing emergency measures to contain the virus.

While the World Health Organisation (WHO) has not flagged the virus as a global health emergency, the rise in HMPV cases has prompted authorities to boost monitoring systems.

Mao Ning, China’s foreign ministry spokesperson, said on Friday that the disease is less severe than COVID-19 virus.

“Respiratory infections tend to peak during the winter season,” Ning said.

“The diseases appear to be less severe and spread with a smaller scale compared to the previous year.”

Unlike COVID-19, there is no vaccine for HMPV yet, its treatment involves managing symptoms.

At least 10 people have been killed after a vehicle drove into a large crowd in New Orleans, a city in Louisiana, United States.

The incident occurred on Wednesday afternoon in the French Quarter, a popular tourist area, when a car sped down Bourbon Street.

Witnesses told CBS News that the driver reportedly got out and began shooting at pedestrians. Police returned fire, and two officers were injured in the exchange.

Anne Kirkpatrick, the city’s police superintendent, described the attack as “very intentional”.

“This man was trying to run over as many people as he possibly could,” she said.

Kirkpatrick said attack began at 15:15 local time (21:15 GMT), adding that most of the victims appeared to be local residents, but the identities of those killed or injured are still being determined.

She said numbers could change, but confirmed 10 people were killed and at least 35 others injured.

She said it is unclear how many victims are tourists and how many are locals but added that she believed that the majority are local to New Orleans.

The superintendent said the Federal Bureau of Investigation (FBI) will take over the investigation into the incident.

Althea Duncan, FBI agent, clarified that the shooting was not a terrorist incident, but noted that “improvised explosive devices” were found on scene.

Duncan said the FBI is working to find out if they are “viable” devices and urged the public to stay away from the area.

Jeff Landry, governor of Louisiana, described the incident as a “horrific act of violence”.

Landry said he is praying for all the victims and first responders at the scene.