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How Switzerland’s largest cities are combating the heat

It has been extremely hot in Switzerland in the past weeks and forecasts call for more of the same. Mountains can provide some relief but what about urban centres? This is how Zurich and Geneva are tackling the heatwave.

How Switzerland’s largest cities are combating the heat
Large trees provide shady canopies. Photo: Pixabay

While meteorologists have referred to this summer as “record-breaking”, with temperatures reaching 40C, the recent heatwave is a not new phenomenon per se.

With temperatures gradually rising for years due to climate change driven by the global warming, Swiss cities have become the so-called “urban heat islands” — densely populated zones where buildings and paved roads trap and absorb the heat and release it into the air.

READ MORE: 40C: Switzerland set for another heatwave

According to a report by RTS public broadcaster, “the effect of heat islands is greater in areas with a high built-up density and fewer green spaces”.

In Geneva, for instance, the districts of Pâquis, Plainpalais, Eaux-Vives, and Pont-Rouge are particularly affected.

In Zurich, the densely populated city centre and the area around the train station are the two hottest spots.

This Youtube video explains where Zurich’s urban heat islands are located.

How do the two cities counteract the effect of these heat bubbles?

According to climatologist Martine Rebetez, the best way to generate coolness is “an urban forest with vegetation on the ground and tall trees so as to create a continuous canopy”.

In Geneva, for instance, 21 percent of the urban zones have these kind of canopies, and the city’s objective is to increase this coverage to at least 25 percent by 2030.

Between 2020 and 2022, 900 trees, have been planted in Geneva specifically for this purpose.

However, as the TSR report points out, this coverage is unequal and seems to be income-based.

“In Florissant, the second-highest income district of the municipality of Geneva, more than 30 percent of the territory is under foliage. In Pâquis, on the other hand, where the median income is much lower, the canopy barely covers 5 percent of the area”.

What about Zurich?

Aside from green areas already in the city, municipal authorities are not only planting new trees but are also replacing those that had to be cut down due to damage.

A new feature is a giant fogger that was recently installed on the Turbinenplatz, one of the largest squares in the city. As soon as the thermometer passes the 30C mark, it sprinkles fine particles of water, cooling the air by up to 10C.

“The contribution of trees to the climate of the city remains unequaled”, said Simone Brander, head of Zurich’s public works at during the inauguration of the fogger.

“Sometimes technical innovations like this artificial cloud can serve as a sensible addition to reduce heat as well.”

READ MORE: How to keep your cool during Switzerland’s heatwave

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What weather can you expect in Switzerland this week?

After a long stretch of scorching temperatures, rain and snow have hit Switzerland over the weekend. Does this mean the summer is definitely over?

What weather can you expect in Switzerland this week?

Since Saturday afternoon, between 40 and 80 mm of rain have fallen in many parts of the country, causing the banks of the Rhine river to partially flood, especially in Diepoldsau (St. Gallen), on the border with Austria.

Overnight from Sunday to Monday, river levels continued to rise in Ticino, Graubünden, and the Eastern Alps as well.

After the heatwave…snow

Though it is only August, snow has fallen at altitudes of between 2,000 and 2,400 metres. And “we can expect 50 centimeters or even more of snow in some areas above about 2,500 meters,” MeteoNews weather service said.

Given this drastic change in weather, the government had already set a level of danger 4 (out of 4) for the rain in the central and eastern regions. 

Strong and rapid rise in water levels, landslides on steep slopes, and flooding in underpasses, basement garages or cellars can’t be ruled out, authorities warned.

Road and rail traffic could also be affected.

What is the forecast for the rest of the week?

On Tuesday, the depression will gradually move away, according to official meteorological service, MeteoSwiss.

By midday on Tuesday, a further 40 to 80 mm of rain is expected along the northern slopes of the central and eastern Alps, as well as in the central and eastern Bernese Oberland, MeteoSwiss said.

On the Central and Eastern Plateau, in the southern side valleys of Valais, in Upper Valais, and in the Eastern Alps, an additional 20 to 50 mm of precipitation is forecast.

The snowfall limit will drop to around 1,900 meters on Tuesday.

Does this mean we should say goodbye to the summer?

Not necessarily.

After the wet and cool weekend and beginning of the week, sunshine and higher temperatures are forecast from Wednesday.

However, it looks (at least for now) that the heatwave is over and the temperatures for the rest of the week will not exceed mid.20s.

This is what you can look forward to in your area of Switzerland this week.