At least seven people died and more than 100 were injured after intense thunderstorms hit northern Greece, tearing out tall pine trees and destroying houses in their passing, officials said on Thursday.
The area affected, Halkidiki, is a peninsula with sandy beaches that is popular with tourists. Thessaloniki, the second-biggest city in Greece, is just to the north.
Kostas Pahinis, fire brigade commander for Central Macedonia, the region that includes Halkidiki, said by phone on Thursday that the storms had been so severe that a kind of tornado had developed.
“It is the first time this has happened to us,” Mr. Pahinis said. “It ripped out more than 500 trees,” he added.
The fire service said that a warning about winds and rain had been issued but that the intensity of the storms had been totally unexpected.
Six of those who died were foreign nationals, Mr. Pahinis said, with the count of those injured at 102.
At about 10 p.m. Wednesday, residents and vacationers were forced to seek cover when a strong wind began blowing across the region, carrying away beach umbrellas and aluminum roofs. The sudden change came as a surprise to many, after several days of clear, hot weather.
An older Czech couple died when the wind blew away their camping trailer, while a 54-year-old Romanian woman and her 8-year-old son were killed on the beach after the roof of a nearby taverna collapsed in Nea Plagia, a small, seaside area in the western part of Halkidiki, according to fire brigade officials.
A Russian man and his 2-year-old son died after a tree collapsed near Potidea Palace, a four-star hotel in which they were staying, the officials said.
The Greek Ministry of Foreign Affairs posted a message of condolence on Twitter on Thursday.
The fire service in Polygyros, the capital of Halkidiki, received more than 600 calls for help on Wednesday night and early Thursday morning, according to the Greek fire service website, while 140 firefighters, 44 firefighting vehicles, 21 ambulances and a doctor in a mobile unit were deployed. A state of emergency was also declared.
Melina Meletlidou said she was in Nea Potidea, a seaside town in the western part of the Halkidiki Peninsula, when the storm hit. At about 9:30 p.m., Ms. Meletlidou, her husband, their two children and her sister drove back from dinner at a taverna nearby to the house they had rented, she said.
It was so hot that they had to turn on the air-conditioning during their short drive, Ms. Meletlidou remembered. “Nothing suggested what would follow,” she said by phone on Thursday, adding that, half an hour later, the weather had changed completely.
“The wind was so strong that we were trying to close the windows but it kept throwing us back,” she said. Soon, power was out, and objects from inside and outside the house were flying around.
“The wooden ceiling was creaking, the windows broke, water was running on the walls, tree branches and roof tiles were coming in through the windows,” she said.
The strong wind and downpour lasted about 15 minutes, according to Ms. Meletlidou. “But to us it felt like eternity,” she added. “We felt like we were going to die.”
Another vacationer, the Rev. Ioannis Zezios, who had traveled to Halkidiki from his home in Nymphaion, a village in northwestern Greece, said by phone on Thursday that huge trees had been “ripped in half,” while “electricity pylons fell to the ground.”
“It started raining, thundering and lightning, and then everything happened in 15 minutes,” he added. Some areas also received hail, according to Dimitris Karasavvidis, the fire brigade commander for Halkidiki.
Charalampos Stergiadis, the head of civil protection in Central Macedonia, said by phone on Thursday that the streets were being cleared of fallen trees and debris, and efforts were underway to reinstate power in all houses.
“We’re trying to preserve life as it was,” he said. “It was an unprecedented phenomenon.”
Zanis Prodromos, a professor of meteorology and climatology at the Aristotle University of Thessaloniki, said the storms had been “definitely an extreme phenomenon.”
He said that Halkidiki had been struck by a “mesoscale convective system” — a collection of thunderstorms — that operated in high wind speeds. It was not unusual for whirlwinds to develop as part of a mesoscale convective system, he added.
Though climate change cannot be directly blamed for extreme weather, warming temperatures do increase the likelihood of such phenomena, Professor Prodromos said.
Almost a year ago, deadly wildfires swept another seaside area, Mati, a settlement in southern Greece outside Athens, killing more than 100.