The sunset had an orange glow and so does the new heat alert level for Paris.

Authorities around the French capital have issued an orange alert for intense heat — the second-highest level on its scale — as very hot temperatures are expected across continental Europe this week.

France’s national weather agency Meteo France said the heat wave beginning Monday is expected to last all week with temperatures of up to 40 degrees Celsius (104 degrees Fahrenheit) across the country. The peak is expected Thursday.

In Paris, charity organizations are patrolling the streets to provide water to homeless people and local authorities have organized air-conditioned places where they can seek shelter.

Meteorologists say the heat wave is caused by hot winds coming from the Sahara Desert.

The alert system was introduced in France following the summer of 2003, which saw an estimated 15,000 heat-related deaths, many of them older people left in city apartments and retirement homes that were not air-conditioned.

French Health Minister Agnes Buzyn said Monday that “everything is ready, in retirement homes, in hospitals, in transports.”

“Yet when people are fragile, even when everything is organized, there’s always a higher mortality rate,” she warned.

Organizers at the Women’s World Cup, which is being hosted by France, could be faced with implementing FIFA heat precautions, since knockout soccer games are being played every day this week except Wednesday and Sunday. Those precautions include holding official cooling breaks or even postponing the match if the heat at the stadium is too high. Luckily, most of the women’s games are being held at night.

Similar heat is also expected in Belgium, Switzerland and Germany.

In Germany, temperatures above 40 degrees C are possible in some places on Wednesday, topping the country’s previous June record of 38.2 degrees Celsius (nearly 100.8 degrees Fahrenheit) set in Frankfurt in 1947.

Rescue services have urged people to look out for young children, the elderly and those with compromised immune systems who are at particular risk in high temperatures.

Parts of northeastern Germany are also at high risk for forest fires. Authorities in the eastern state of Brandeburg, which circles Berlin, say the risk of forest fires is at the highest level in the coming days.

Scientists say measurements show heat waves in Europe are becoming more frequent.

Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research said “monthly heat records all over the globe occur five times as often today as they would in a stable climate.”

“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,” he added.

Dim Coumou, a scientist at the Free University of Amsterdam, said melting Arctic sea ice is also affecting atmospheric circulation, which in turn makes extreme heat more likely.

“Data analysis shows that the normally eastward travelling summer circulation of the Northern Hemisphere mid-latitudes has slowed down, including the Jet Stream,” he said. “This favors the buildup of hot and dry conditions over the continent, sometimes turning a few sunny days into dangerous heat waves.”

(AP)