New floods have hit Catalonia and Andalusia in Spain in recent hours, but also Sicily in Italy. What are the causes of these repeated disasters and how can we explain such material and human damage?
Spain and Italy have been hit again in recent hours by torrential rainswith very significant flooding and damage. In Spain, the regions of Malaga, Andalusia, Tarragona, Catalonia, but also Valencia have been placed on red alert: the result is flash floods, sometimes historic, tornadoes, a devastated railway network and a flooded Malaga hospital.
In Italy, Sicily was heavily impacted during the night from Tuesday to Wednesday by extreme rains in the region Catanialeading to landslides, floods, and washing away cars, sections of road and even sections of motorway! How can we explain the extent of this destruction in these two countries? Why such human and material disasters?
Cold drop and very hot Mediterranean
These terrible conditions can be explained firstly by the weather situation. In Spain, it is a cold drop (or DANA, in local jargon), that is to say very cold air at altitude in the form of a small ball which transited from the Basque country to Portugal, generating on the East coast Spanish a flow from South-South-East bringing unstable and stormy puffs from the Mediterranean.
In Sicily, up to 500mm of rain was recorded in less than 6 hours in the north of the Catania region. An extreme phenomenon which obviously caused landslides and floods, in a relief area.
At the same time, between this call of cold air, warm air rising from North Africa and another cold area over central Europe, a very small low pressure minimum formed between Italy and Tunisia, also leading to stormy rises over Sicilyin a southerly flow (the winds rotate counterclockwise around a depression).
To this is also added the climatic context, through the warming of the air : one degree more is equivalent to 7% more humidity in the atmosphere, and therefore more intense rain. More the warming of the Mediterranean also comes into play : this sea is abnormally warm at the moment (24° off Sicily), which acts as fuel for storms, aggravating their violence.
Result: 133 liters of water per square meter (133 mm of rain) fell yesterday afternoon in Malaga, including 80 liters in just one hour! In Sicily, between Acireale, Giarre and Riposto, the weather services recorded 500mm of rain in less than 6 hours! An extreme phenomenon which, as a reminder, devastated the Valencia region in Spain 15 days ago, with locally more than 600mm in 24 hours…
Finally, last aggravating factors, these unfortunately stationary stormsconstantly replenished by the heat of the Mediterranean, stumbled on reliefswith rugged slopes, such as Etna in Sicily, promoting runoff and flooding, all on areas that are far too urbanized by humans. Hence soils incapable of absorbing excess water, hence this damage…
