NEW YORK — Perilously cold temperatures threatened millions across the United States on Monday in the wake of a sprawling winter storm that left at least 30 people dead as it knocked out power and paralyzed transportation.

A frigid, life-threatening Arctic air mass could delay recovery as municipalities from New Mexico to Maine tried to dig out after the storm, which dropped a vicious cocktail of heavy snow, wind, freezing rain and sleet.

Forecasters warned that much of the northern half of the country will see temperatures that are "continuously below freezing through Feb 1", and "record-low temperatures tonight across the South are particularly dangerous in the wake of the weekend winter storm with many still without power", the National Weather Service said on X.

While skies began clearing in parts of the US, relentless snowfall in the northeast meant parts of Connecticut saw more than 56 centimeters of snow, with more than 40.6 cm recorded in Boston.

The storm was linked to at least 30 deaths, according to a compilation of state government and local media reports, with causes including hypothermia as well as accidents related to traffic and snowplows.

One man in New Jersey was found in the snow, unresponsive, with a shovel in his hand.

In New York, eight more people were found dead amid plummeting temperatures, and an investigation to determine the causes was underway. It was not known if all of these fatalities were storm-related.

Power outages

Electricity began blinking back on across the south, but as of Tuesday morning, more than 540,000 customers remained without it, according to the Poweroutage.com tracking site.

Tennessee, Texas, Mississippi and Louisiana — southern states unaccustomed to intense winter weather — were especially affected.

Around 190 million people across the US were under some form of extreme cold alert, the National Weather Service told Agence France-Presse.

The residents of the Great Lakes region woke up to extreme temperatures that could cause frostbite on exposed skin within minutes. In parts of Minnesota and Wisconsin, the National Weather Service reported on Monday morning that temperatures were as low as — 30.6 C, with windchills exacerbating the bite.

National Weather Service meteorologist Allison Santorelli told AFP that this storm recovery was particularly arduous because so many states were affected, meaning northern states with more winter supplies were unable to share their resources with less-prepared southern regions.

"A lot of those locations don't have the means or the resources to clean up after these events," she said. "We're particularly concerned about the folks in those areas that are without power right now."

At least 20 states, including the capital, Washington, were under states of emergency to deploy emergency personnel and resources.

The snowfall and biting, icy pellets that pummeled cities left roads impassable, along with canceled buses, trains and flights. Thousands of departures and arrivals were scrapped over the weekend.

Agencies via Xinhua