Three people died on Tuesday as heavy snowfall fell and gale-force winds hit Greece, disrupting road and sea transport as well as halting Covid vaccinations in Athens.
The cold front, dubbed "Medea" after the mythical Greek sorceress of the Argonauts, sent temperatures plunging, with a maximum low of minus 19 degrees Celsius in the northwestern city of Florina.
"The last time we saw so much snow in the centre of Athens was in February 2008," meteorologist Costas Lagouvardos told AFP.
On the island of Evia near Athens, two elderly men suffering from respiratory problems died after their breathing apparatus failed during a power outage, state TV ERT reported.
On Crete, a livestock farmer in his 60s was found dead in the snow outside his granary at the village of Kaminaki in the east of the island, TV ERT added.
The rare phenomenon prompted authorities to cancel all coronavirus vaccinations planned in the capital for the day.
Evia, Greece's second largest island, has been without power for two days, and scores of falling trees caused local outages in some parts of the greater Athens area.
Over a dozen municipalities in the capital have been affected, officials said.
'Truly exceptional problem'
"Our big concern is the electricity grid," Prime Minister Kyriakos Mitsotakis said after an emergency cabinet meeting. "We need patience to resolve this problem which is truly exceptional."
The weather conditions also sparked concern about conditions for thousands living in migrant camps around the country.
Over the past few days, the United Nations' refugee agency UNHCR has sent radiators to the camps around the country where tens of thousands of asylum seekers have been struggling with the cold and hail.
Additional sleeping bags and blankets have also been handed out, a migration ministry source told AFP.
In the camp of Elaionas near Athens, some 200 refugees on Tuesday had to be temporarily rehoused in containers and an indoor gym after their tents were damaged by snow, according to a migrant support group.
Authorities shut down the main motorway between Athens and Greece's second city Thessaloniki late Monday to prevent traffic backups, while winds of up to 100 kilometres an hour halted shipping between the Greek mainland and the Aegean islands.
The snow that fell through most of the day Monday snarled traffic in the city centre on Tuesday as well as in the northern suburbs.
The snow also turned the sandy beaches of the Athens seafront white.
The weather was forecast to improve from Wednesday.
North Carolina hit by tornado
A tornado killed at least three people when it ripped through the state of North Carolina, officials said on Tuesday, while elsewhere much of the US remained gripped by a record cold snap.
The twister tore into the southern part of the state late Monday, particularly impacting two coastal communities in Brunswick County.
"At this time, there are three confirmed fatalities and 10 confirmed injuries," Brunswick County Emergency Services said in a statement.
"It is estimated that at least 50 homes were affected in the incident and several power lines were damaged, causing power outages."
Photos and video broadcast by US media showed downed trees, flattened homes and smashed cars.
Sheriff John Ingram told a press conference there would "be a long recovery process".
"This is something unlike I've ever seen," he said, cited by US media.
Elsewhere across the United States, much of the country remained gripped by a deadly cold snap fueled by frigid Arctic air that has brought record low temperatures.
The National Weather Service (NWS) said a new winter storm was emerging in the Southern Plains area - which includes parts of Texas, Oklahoma and Kansas.
The NWS on Monday warned of an "unprecedented and expansive area of hazardous winter weather" from coast to coast, with more than 150 million Americans under winter weather advisories.
The freezing conditions have killed at least 10 people and have particularly afflicted regions unaccustomed to snow and sleet.
A power outage tracker reported more than 2.7 million people were without power in Texas, where temperatures in the major metropolis of Houston dipped to -9 degrees Celsius, well below average February lows.