Pushed by westerly winds, the very fine particles of smoke emitted by the mega-fires currently ravaging the western United States have now reached Switzerland. Strong concentrations, but temporary, which are not good for health.
At least 30 people have died in the fires and authorities have ordered mass evacuations. US President Donald Trump traveled to California for a whirlwind visit.
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And during this time, the very fine particles of smoke traveled more than 8000 kilometers to reach Europe. They hit Switzerland on Sunday.
First on northern Europe
These particles were detected on September 11 in northern Europe, explained Tuesday Lionel Fontannaz, meteorologist at MétéoSuisse, in La Matinale. And little by little, this plume of smoke moved south and reached Switzerland. On Monday, the signal was even stronger in the Jungfrau region (BE).
“If we look at a satellite image, we can see this plume of smoke very clearly over the whole of central Europe”, continues Lionel Fontannaz. “You might think they are high clouds, but when you look at the temperature of these particles, you can see that they are not as cold as high clouds. So we really have proof that these are that plume of smoke that is over Europe. “
It is common for aerosols to travel in the atmosphere over very long distances, notes Lionel Fontannaz. “On the other hand, what is exceptional are these fires in California, which create a large mass of smoke particles. And if there are high concentrations, it is obviously not good for your health. But it will be. anyway, passenger “, underlines the meteorologist.
>> Also listen to the analysis of Christian Kull, professor of geography at the University of Lausanne, in La Matinale:
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Radio interview: Pauline Rappaz
Web adaptation: Jean-Philippe Rutz