More searing temperatures fuelled wildfires and prompted health warnings across Europe on Wednesday, as a blaze in Turkey forced the closure of the Dardanelles shipping lane and winds fanned the flames in Greece where 20 people have already been killed.

France, which widened its heatwave red alert in the south of the country, said it would scale back production at a nuclear power plant as high temperatures curbed the cooling water supply.

In Greece, firefighters were battling a blaze for a second day close to Athens and the authorities warned that heat and winds risked fuelling more wildfires, a day after 18 bodies, probably migrants, were found in a charred northern forest.

A wildfire north of Athens that erupted on Tuesday has smothered the capital in smoke and ash, spreading to the town of Menidi, from where about 150 people were evacuated from three nursing homes. Police ordered others to leave as a helicopter clattered overhead to drop water to douse the conflagration.

“The fire went out for half an hour… but with these very strong winds, it’s been alternately starting and then stopping again,” 60-year-old resident Dimitris Armenis told Reuters.

A volunteer carried an icon of the Virgin Mary out of a burning monastery, while police raced to remove large gas canisters from the ash-covered premises.

Another 700 people were moved from a migrant camp in the Amygdaleza region, about 25 kilometres north of Athens, a Migration Ministry official said.

Greek Climate Crisis and Civil Protection Minister Vassilis Kikilias said 355 wildfires had broken out since Friday, with 209 new blazes in the last 48 hours alone.

Near the northeastern Greek port city of Alexandroupolis, dozens of hospital patients, some on stretchers, others attached to IV drips, were evacuated onto a ferry as a fire in the area blazed for a fifth day.

The authorities were trying to identify the 18 bodies discovered on Tuesday in Dadia forest in the Evros region on Turkey’s border, on a common route for migrants from the Middle East and Asia trying to cross into the European Union.

Shipping disrupted

On the Turkish side, the authorities temporarily closed the Dardanelles Strait to shipping, creating a queue of about 100 cargo ships, to allow helicopters and planes to scoop up water to contain a forest fire in the area raging for a second day.

The strait, linking the Aegean Sea and the Black Sea, is a major shipping route for commodities such as oil and grains.

A Turkish goat herder had told people by mobile to flee a wildfire threatening a village in Turkey’s northwestern Canakkale province: “Let it burn if you must. Just get out of the village, don’t stay there any longer.”

The French national weather service, Meteo-France, reported the country’s highest average temperature for the late summer period after Aug 15 since records began in 1947. It said some areas of southern France would experience temperatures of 42 degrees Celsius.

The authorities widened a heatwave red alert for the south of the country, while officials urged some mountain climbers to postpone their activities and told grape pickers to work in the morning to avoid the extreme heat.

French power producer EDF issued a production warning for the Saint Alban nuclear power plant on the Rhone river because of a shortage of cooling water. Similar warnings have been issued this summer for other plants.

In Spain, which is enduring its fourth heatwave of the summer, people who normally receive food and other necessities from the non-governmental organisation Fundacion Madrina were also handed fans on Wednesday to cope with high temperatures.

Firefighters on the Spanish island of Tenerife have brought a blaze that has devastated forests under control, allowing about 8,000 evacuees to return.

But local farmers protested about the use of scarce water resources to fight the blaze and police said they had arrested an 80-year-old man for throwing stones at a firefighting helicopter, forcing it to make an emergency landing.

Italy issued heatwave red alerts about “emergency conditions” that the health ministry says could endanger the healthy as well as those who are frail in 17 of its 27 main cities for Wednesday and Thursday, including Rome, Milan, Florence and Venice. The number was set to rise to 19 on Friday.