The temperature anomaly across Europe as of Tuesday.
  • Countries including France, Germany, Spain, Switzerland, and Portugal are expected to experience a massive heat wave starting Wednesday, with hot air coming from the Sahara.
  • Temperatures are expected to rise as high as 45 degrees Celsius, or 113 Fahrenheit, this week.
  • The forecast is so intense that one Spanish meteorologist tweeted, "Hell is coming."
  • Some 15,000 people in France died when temperatures hit similar heights in August 2003. Officials in Paris have already put the city on high alert.
  • Scientists attribute it to global warming and warn of more such heat waves if countries don't cut their greenhouse-gas emissions soon.
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Western Europe is bracing for an intense, dangerous, and possibly even deadly heat wave this week, with temperatures due to soar as high as 40 degrees Celsius.

Countries including France, Spain, and Portugal are expecting record-breaking temperatures starting Wednesday, while the rest of the continent is also set to face temperatures much higher than normal.

It's not clear when the heat wave will end.

Scientists have attributed the soaring temperatures to the combination of a storm over the Atlantic Ocean and high pressure over central Europe, which is importing hot air from the Sahara.

Read more: Paris opened extra swimming pools, set up mist machines - and postponed thousands of school exams - ahead of a killer heat wave looming over Europe

Here's what's being forecast:

  • Parts of France could reach 39 degrees Celsius on Wednesday, the national weather agency Météo France reported.
  • Areas in southern France are forecast to reach as high as 45 C on Friday, meteorologist Guillaume Woznica tweeted.
  • Berlin is expecting temperatures as high as 38 C by Thursday, the BBC said. Major cities like Frankfurt and Hamburg are also expecting temperatures in the mid-30s Celsius.
  • Most of Spain is expecting temperatures of at least 36 C on Wednesday, with the highest at 38 C according to the Spanish meteorological agency Aemet.
  • Large swaths of Switzerland are expecting temperatures of more than 30 C beginning Wednesday, with Geneva predicted to reach 37 C on Wednesday and Thursday, Switzerland's national meteorological agency, Météo Suisse, said.
  • Temperatures in Portugal are expected to hit mid-to-upper 30 degrees Celsius and could further rise to more than 40 C, Axios reported.
  • Parts of Poland are also expected to see temperatures rise to at least 35 to 40 C this week - which is at least 11 to 17 C above normal, The Washington Post reported.

Silvia Laplana, a meteorologist at Spain's state-owned RTVE channel, tweeted images of the forecast temperatures in the country this week with the caption "El infierno is coming." Infierno is the Spanish word for hell.

The sudden spike in temperature could be dangerous because the region is not accustomed to such high temperatures, which could put people at risk of heat-related ailments, Axios said.

Some 15,000 people across France died following a similarly aggressive heat wave in August 2003, when temperatures in the south of France hit as high as 44.1 C, according to France24.

Officials in Paris have put the city in high alert, placing hospitals and care homes on high alert as schools delay exams, Business Insider's Sinéad Baker reported.

Read more: Photos show people playing in historic fountains and eating gelato to cool down ahead of a killer heat wave looming over Europe

Tourists and Parisians cooling off in the water of the Trocadero fountain at the foot of the Eiffel Tower on Monday.

Though heat waves are not uncommon in Europe, this one is unusually early. Experts say climate change is making heat waves more common.

"This increase in heat extremes is just as predicted by climate science as a consequence of global warming caused by the increasing greenhouse gases from burning coal, oil, and gas," Stefan Rahmstorf, a climatologist at the Potsdam Institute for Climate Impact Research, told the Associated Press.

Heat waves like this will continue to worsen if countries do not cut their greenhouse-gas emissions soon, a group of scientists warned in a report published earlier this month.

Read more: How extreme summer heat affects your body and brain

Tourists at a fountain in front of the Pantheon in Rome on Monday.

Recent heat waves around the world have already proved to be deadly.

At least 36 people have died during a prolonged heat wave in India, which has lasted more than 30 days, according to CNN.

Temperatures in Churu, western India, rose above 50 C (122 F) on June 1, the network reported.

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