San Francisco Frontiers - Heatwave across the Med sparks health and fire warnings

The searing heat spreading across the Mediterranean from the Iberian peninsula to the Balkans and Greece comes as climate scientists warn that galloping human-induced climate change is causing more extreme weather, including longer and more intense heatwaves.

Tens of millions of people have already been sweltering in what the National Weather Service called an "extremely dangerous" heatwave across the eastern United States, including in New York and Washington, straining the power grid as people cranked up air conditioning.

Across the Atlantic in Spain, emergency medical staff readied to deal with an expected surge in heatstroke cases, particularly among vulnerable groups such as children, the elderly and people with chronic illnesses.

In neighbouring Portugal, the national meteorological agency IPMA said the heatwave would hit from Saturday, with temperatures passing 40C in the south of the country as well as in the central Tagus and the Douro valleys in the north.

Sunday will be even hotter, the agency added, and two-thirds of the country has already been put on orange alert. Temperatures are expected to hit 42C in the capital, Lisbon.

The risk of fire is at its highest inland in the northern half of Portugal, as well as on the Algarve coast popular with holidaymakers in the south.

France has been gripped by its 50th national heatwave since 1947 for more than a week now, and four regions in southern France were placed under an orange alert on Friday -- the second-highest warning -- as temperatures were expected to reach 35C to 38C locally, and up to 39C inland.

The Meteo France weather agency said surface sea temperatures from the Mediterranean were an "aggravating factor" that could make nights "more stifling".

Nine additional French regions are expected to be placed on orange alert from 12:00 pm (1000 GMT) on Saturday.

- Warnings -

In Italy, the health ministry issued its top red alert for 21 cities this weekend including the capital Rome, the economic powerhouse Milan and Venice, where the rich and famous were celebrating the wedding of Amazon tycoon Jeff Bezos.

People were advised not to go outdoors between 11:00 am and 6:00 pm, and to seek shelter in air-conditioned public places.

In Venice, the temperature was set to hit 32C on Saturday, when Bezos and Lauren Sanchez are expected to be throwing a dance party starring Lady Gaga -- but it will feel like around 36C due to humidity.

In Florence, which was already on red alert on Friday, the temperature is forecast to reach 37C on Saturday, while it will go up to 36C on Sunday in Rome, Milan and Naples.

Across the Adriatic, the authorities in Croatia, Bosnia and Serbia also issued health warnings, while in Albania, firefighters battled Thursday to bring at least eight blazes under control after flames destroyed dozens of homes in the south of the country last weekend.

Further south, weather agencies in Greece forecast a heatwave in the coming days with temperatures of more than 40C, including in the capital Athens.

The country has become particularly vulnerable to summer fires in recent years fuelled by strong winds, drought and high temperatures linked to climate change.

Firefighters said Friday that a forest blaze that had forced evacuations around Athens was under control but warned that scorching temperatures were keeping fire risk at a highly elevated level around the capital and on northern Aegean islands.

Fields, olive groves and some houses were ravaged by the blaze around Athens, which came after another on Greece's fifth-largest island Chios that destroyed more than 4,000 hectares (10,000 acres) of land in four days.

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V.Perez--SFF