The death toll from the severe weather in the United States climbed to 23 on Monday, as millions of Americans faced a polar cold wave that left nearly 600,000 homes without power by evening.

Temperatures are expected to fall further in the coming days under the influence of an Arctic air mass, particularly in northern regions of the country, where the wind chill could reach -45°C.

Heavy snowfall – more than 30 centimeters in about twenty American states – has led to power outages.

According to the specialist website poweroutage.us, some 600,000 customers were still without power on Monday evening, mainly in the southern United States, where ice brought down power lines.

Nearly 200,000 people are affected in Tennessee and more than 147,000 in Mississippi.

"The power cuts could last for several more days as the authorities are struggling to recover (from the storm). Most of these regions do not have the means or the resources to clear up after such events, as they are not used to it," meteorologist Allison Santorelli told AFP.

In the Great Lakes region of the northern United States, residents woke up to extreme temperatures, below -20°C, and as low as -30 in parts of Minnesota and Wisconsin (north), according to the National Weather Service (NWS).

Dave Radell, a meteorologist based in New York, told AFP that the snow that fell during the storm was "very dry" and "powdery," meaning that the wind can easily disperse it, hindering road clearing efforts and reducing visibility.

Considered by some specialists to be one of the worst winter episodes in recent decades in the United States, the storm is accompanied by ice accumulations with potentially "catastrophic" consequences, according to the NWS.

Polar Vortex

These extreme conditions resulted in the deaths of at least 23 people, according to a count compiled using local US media.

In Texas, authorities confirmed the death of a 16-year-old girl killed in a sledding accident. Two people died of hypothermia in Louisiana, and one in Iowa in a collision.

Eight people were found dead in New York, and an investigation has been launched to determine the causes of death.

A state of emergency has been declared in about twenty states as well as in the capital, Washington, and transportation has been severely disrupted.

Several major airports, in Washington, Philadelphia and New York, were virtually at a standstill, while more than 21,000 flights have been cancelled since Saturday and thousands more have been delayed, according to the FlightAware website.

The storm is linked to a deformation of the polar vortex, a mass of air that usually circulates above the North Pole, but which has stretched southward.

Scientists believe that the increasing frequency of these vortex disturbances could be linked to climate change, although the debate is not settled and natural variability also plays a role.

An avowed climate skeptic, Donald Trump nevertheless used the storm as a pretext to express his skepticism again on his Truth Social platform, in a message partly in capital letters: "Could the environmental insurgents please explain to me: what happened to global warming?".