The scorching heat of summers that Belgium and the rest of Europe experienced this year is in complete contrast with that of 2021, characterized by severe floods. But both extreme phenomena are linked, as per experts.
“They are two sides of the same coin,” says François Massonnet, a researcher and climatologist at UCLouvain, who says that both are due to a blocking phenomenon accentuated by the rise in temperatures observed over the last 30 years.
“Weather is dictated by the general atmospheric circulation; the configuration of low and pressures, and where and when they occur,” says Massonnet. “What happened this summer is that an area of high pressure – an anticyclone, one that brings us hot and dry weather – has been blocked for quite a long time on our regions and the consequence of this is that all the depressions, which bring us cooler and wetter weather, that arrive from the west and that should normally bring us rain, are sent elsewhere by the anticyclone.”
“We then speak of a blockage,” he explains. “And so, when this anticyclone stays in the same place for a very long time, we no longer have precipitation, and it starts to be really dry and hot because the cloud cover is very weak with an anticyclone, and it is this persistence that makes us have a very hot and very dry summer.”
On the other hand, “in 2021, it was a big depression that remained anchored on our regions,” Massonnet says. “So, we also had an atmospheric situation that had been blocked, but which brought an area of intense precipitation that did not move. It stayed for three to four days over our country and started pouring all the moisture that was in the air column over parts of Belgium.”
These deadlock situations are not new, says François Massonnet. “We have had them for a long time, and we will always have them.”
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