San Francisco Frontiers - US monster storm kills 30

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

Forecasters warned that much of the northern half of the country will see temperatures that are "continuously below freezing through February 1," the National Weather Service said in an X post.

It added that "record low temperatures" hit southern states, which are unaccustomed to intense winter weather.

While skies began clearing in parts of the country, relentless snowfall in the northeast meant parts of Connecticut saw over 22 inches (56 cm) of snow, with more than 16 inches (40.6 cm) recorded in Boston, Massachusetts.

- Deadly plane crash -

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, sledding, ATVs and snowplows.

Seven people were killed when the small plane they were traveling in crashed while taking off in a snowstorm in Bangor, Maine, the Federal Aviation Administration said.

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

In New York City, 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.

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

Tennessee, Texas, Mississippi and Louisiana in the south were especially impacted.

More than 9,000 flights were disrupted, as the storm paralyzed transportation across the country.

"We don't know if we are going to make it or not. We've been here since Sunday," Alan Vazquez told AFP at Dallas–Fort Worth airport in Texas.

Nashville Mayor Freddie O'Connell told journalists that trees were continuing to fall under the weight of encrusted ice across the Tennessee capital city, sometimes knocking out power that had already been restored.

Nashville and other municipalities across the country were establishing emergency warming shelters.

NWS meteorologist Allison Santorelli told AFP this storm recovery was particularly arduous because so many states were impacted -- 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."

- Polar vortex -

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

The storm system was the result of a stretched polar vortex, an Arctic region of cold, low-pressure air that normally forms a relatively compact, circular system but sometimes morphs into a more oval shape, sending cold air pouring across North America.

Scientists say the increasing frequency of such disruptions may be linked to climate change, though the debate is not settled and natural variability plays a role.

"That makes it even more challenging," he said.

N.Wilson--SFF