A heatwave sweeping southern Europe that has caused hundreds of deaths and huge wildfires in past weeks showed some signs of abating on Monday but continued to move north, including towards Britain where authorities issued an extreme weather warning.

Much of Europe is baking in a heatwave that scientists say is consistent with climate change and has pushed temperatures into the mid-40s Celsius (over 110 Fahrenheit) in some regions, with wildfires raging across tinder-dry countryside in Portugal, Spain and France.

Temperatures in some parts of southern Europe began to ease over the weekend but thousands of firefighters across the region still battled to contain hundreds of wildfires and authorities said the risk of further blazes remained extremely high.

Spain was facing the eighth and last day of a more than week-long heatwave on Monday, which caused more than 510 heat-related deaths, according to estimates from the Carlos III Health Institute.

In Spain, helicopters dropped water on the flames as heat above 40 degrees Celsius (104 Fahrenheit) and often mountainous terrain made the job harder for firefighters.

With fires burning thousands of hectares in Galicia, Castille and Leon, Catalonia, Extremadura and Andalusia, Spain mourned the death of one firefighter in the northwestern province of Zamora on Sunday evening. Almost the entire country faces a extreme fire risk.

"There are never words to thank the immense work of those who fight the fires tirelessly," Prime Minister Pedro Sanchez said on Sunday night in a condolence message on Twitter.

Shocked residents watching thick plumes of smoke rising above the central western Jerte valley said the heat was making their previously green and cool home more like Spain's semi-arid south.

"Climate change affects everyone," said resident Miguel Angel Tamayo.

A study published in June in the journal "Environmental Research: Climate" concluded it was highly probable that climate change was making heatwaves worse.

More than 1,000 deaths have been attributed to the nearly week-long heatwave in Portugal and Spain so far. Temperatures in Spain have reached as high as 45.7 degrees Celsius (114 degrees Fahrenheit).

Fires were raging in several other regions including Castille and Leon in central Spain and Galicia in the north on Sunday afternoon. Firefighters stabilized a blaze in Mijas, in Malaga province, and said evacuated people could return home.

National emergencies

Belgium and Germany were among the countries expecting the heatwave to hit them in coming days.

Britain was on course for its hottest day on record on Monday with temperatures forecast to hit 40 Celsius (Fahrenheit) for the first time, forcing train companies to cancel services, schools to close early and ministers to urge the public to stay at home.

The government has triggered a "national emergency" alert as temperatures were forecast to surpass the 38.7C (102F) recorded in the Cambridge University Botanic Garden in 2019 on Monday and Tuesday.

Britain's national weather forecaster issued its first red "extreme heat" warning for parts of England. Rail passengers were advised to only travel if absolutely necessary and to expect widespread delays and cancellations.

British pensioners William and Ellen McCurdy had fled for safety with other evacuees in a local sport center from their home on Saturday as the fire approached.

"It was very fast ... I didn’t take it too seriously. I thought they had it under control and I was quite surprised when it seemed to be moving in our direction," William, 68, told Reuters.

"We hoped we wouldn't get to this situation but for the first time ever we are forecasting greater than 40C in the U.K.," climate attribution scientist at the Met Office, Dr Nikos Christidis, said.

"Climate change has already influenced the likelihood of temperature extremes in the U.K.. The chances of seeing 40C days in the UK could be as much as 10 times more likely in the current climate than under a natural climate unaffected by human influence," he said.

In France, wildfires had spread over 11,000 hectares (27,000 acres) in the southwestern region of Gironde, and more than 14,000 people have been evacuated, regional authorities said on Sunday afternoon.

More than 1,200 firefighters were trying to control the blazes, the authorities said in a statement.

France issued red alerts, the highest possible, for several regions, with residents urged "to be extremely vigilant."

In Italy, where smaller fires have blazed in recent days, forecasters expect temperatures above 40 degrees Celsius in several regions in coming days.

Drought in Portugal

Around 1,000 firefighters tried to control 13 forest and rural fires in the center and north of Portugal, the largest being near the northern city of Chaves.

Portugal's Health Ministry said late on Saturday that in the last seven days 659 people died due to the heatwave, most of them elderly. It said the weekly peak of 440 deaths was on Thursday, when temperatures exceeded 40 degrees Celsius (104 degrees Fahrenheit) in several regions and 47 degrees Celsius at a meteorological station in the district of Vizeu in the center of the country.

By Saturday, there were 360 heat-related deaths in Spain, according to figures from the Carlos III Health Institute.

Portugal was grappling with extreme drought even before the recent heatwave, according to data from the national meteorological institute. Some 96% of the mainland was already suffering severe or extreme drought at the end of June.

Emergency and Civil Protection Authority Commander Andre Fernandes urged people to take care not to ignite new fires in such bone-dry conditions.

In Greece the fire brigade said on Saturday 71 blazes had broken out within a 24-hour period.