What is a “medicane”, this weather phenomenon responsible for deadly floods in Libya?

Libya is in mourning. Several thousand people died in the floods of Derna following bad weather caused by storm Daniel which affected this coastal city.

This flash flood also forced the displacement of 30,000 people follows a “medicane”, a destructive weather phenomenon that could intensify in the years to come due to global warming. Regularly used by scientists and meteorologists, this term comes from the contraction of the words “ Mediterranean » and “hurricane” (Editor’s note, hurricane).

This cyclone rare Mediterranean tropical has similar formation mechanisms to other cyclones, although it can form over colder waters. These Mediterranean storms are generally smaller and weaker than their tropical counterparts and have more space to develop. Their maximum power is generally equivalent to a Category 1 hurricane over the Saffir-Simpson scaleor a speed of 119 to 153 km/h.

Medicans usually form in the fall

In addition to these violent winds, the medicanes are accompanied by raging rains, as during the storm Daniel which dumped up to 170 mm of rain in less than two days on Cyrenaica, in northern Libya, where rain is very rare in this season.

VIDEO. Devastating floods in Libya: the city of Derna continues to count its dead

Medicanes usually form in the fall when the Mediterranean Sea is still above 20°C after summer, in the western Mediterranean and the region between the Ionian Sea and the North African coast, says Suzanne Gray, a professor at Department of Meteorology, University of Reading.

“In an unstable air m, these depressions are supplied with energy by the warm waters of the Mediterranean,” explains Meteo France. “The very strong convection will contribute to deepening the depression. Their genesis, however, is different, an eye can then form,” continues the meteorological service.

While hurricanes move from east to west, medicanes tend to move from west to east, which explains why Storm Daniel hit Bulgaria, Greece and Turkey before reaching Libya.

“Climate change increases the intensity of medicines”

While it is difficult to draw climatic conclusions from medicanes because of their rarity, experts say that global warming sea ​​surface temperaturescaused by climate change, will make the phenomenon even more intense, even if they could become less frequent.

Entire neighborhoods of the town of Derna in Libya disappeared following floods caused by the Daniel Medican, sweeping away at least 2,300 people.
This event is multifactorial, both climatic, pedological and political:
➡️ Rising air temperatures due to… pic.twitter.com/PEONktFh4L

— Dr. Serge Zaka (Dr. Zarge) (@SergeZaka) September 13, 2023

“We think that the climate change increases the intensity of the most powerful medications,” says Liz Stephens, professor at the University of Reading. And “we are convinced that climate change is increasing the precipitation ociated with such storms,” she adds.

As a reminder, in July the Mediterranean reached its highest temperature never recorded while Europe was faced with a series of exceptional heat waves.

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