Recent pictures of the devastating flash floods attributable to Storm Daniel in Greece hit near dwelling actually and figuratively. As a Greek who has accomplished a PhD and labored for the previous eight years on flash floods, the scenes unfolding throughout my homeland are painfully actual: a stark reminder of the broader environmental challenges we face each on an area and a world scale.
These unprecedented flash floods have been triggered by rainfall from the arrival of Storm Daniel on Monday September 4 which additionally affected Turkey and Bulgaria. The following day, within the village of Zagora, a record-breaking 754mm of rain fell in simply 18 hours, leaving elements of the area of Thessaly in disaster and unable to reply.
To put this in perspective, London will get about 585mm of rain over the course of a yr whereas Thessaly will get 495mm, which means that on Tuesday, about 1.5 years’ price of rain fell in 18 hours. Imagine probably the most torrential rain you will have ever skilled, maybe a cloudburst lasting 20 minutes or so. Now think about it raining that tough however with out pause for a whole day.
Flash flooding is brief in period however extraordinarily intense, and usually occurs inside six hours of heavy rainfall. Unlike common floods, which develop extra slowly and could be predicted upfront, flash floods catch individuals off guard as a result of their fast onset and are not often recorded within the area.
National Observatory of Athens/meteo.gr, CC BY-SA
Across the three affected international locations the floods have killed at the least 18 individuals, with many others in search of refuge on their rooftops. There are ongoing energy and water outages, infrastructure has been broken, homes and even total villages have been fully submerged.
I requested Andrew Barnes, a tutorial on the University of Bath with experience in utilizing AI to analyse excessive occasions why this occasion was so distinctive. He instructed me that all through Tuesday, a powerful low-pressure centre shaped throughout the south of Greece creating a big rotating climate system often known as a cyclone.
This cyclone carried massive rain clouds from each the Mediterranean and Aegean Sea between Greece and Turkey. But it didn’t dissipate, and as an alternative its low-pressure centre moved southwest and settled simply south of Italy, with its bands of rain clouds additionally transferring south and overlaying most of mainland Greece.
Trending throughout the area
It is essential to stress that flash floods aren’t confined to Greece alone. They are the truth is a part of a broader sample of utmost climate that has turn into extra intense and frequent throughout the Mediterranean area.
Researchers who checked out 150 years of flood knowledge within the Mediterranean discovered that the majority have been flash floods, with their highest incidence through the summer time and autumn months. The area is especially prone to those floods as a result of mixed results of local weather change and urbanisation. The latter has elevated city improvement in flood-prone areas and elevated impervious surfaces (like roads and pavements), stopping the pure absorption of water into the bottom.
The Intergovernmental Panel on Climate Change’s chapter on the Mediterranean area issued a warning that excessive rainfall occasions are going to happen extra usually and be much more intense, elevating the danger of flash floods. This warning, together with information of flash floods in 2023 in Spain, Italy, Turkey, Bulgaria, France and Greece, underscores the pressing want for proactive measures to deal with these climate-related challenges.
Research is advancing
Flash floods is likely to be uncommon, however they’re extreme sufficient to be a matter of great concern. Fortunately, analysis has superior significantly lately. We’re now higher capable of forecast when flash floods would possibly occur, which areas is likely to be prone, and to evaluate their impression in real-time.
My colleagues and I are engaged on a mission that mixes historic documentary sources and trendy hydraulic modelling. This means we will make clear previous floods and higher perceive the dangers they pose, serving to us design efficient mitigation methods for the long run. Practically, within the case of a flash flood some fundamental however essential actions could be discovered on the poster beneath.
An entire eradication of flooding is neither technically possible nor economically reasonably priced. Instead on a bigger scale it’s key to begin figuring out flash-flood inclined areas particularly in catchments with historic flash floods. We ought to then deal with advocating for local weather motion and resilience measures, which could be something from “onerous” defences like new flood partitions, by means of to insurance policies and higher public consciousness of the dangers. Only it will provide hope of a safer and extra resilient future.
Ioanna Stamataki has obtained funding from EPSRC, The Leverhulme Trust and the British Council.