The episode of extreme rainfall that affected the east of the Iberian Peninsula at the end of October 2024 left a devastating mark on the province of Valencia. In some areas, such as Turís, more than 700 litres per square metre were recorded in 24 hours; in other words, in just one day, more water fell than the average rainfall in mainland Spain in an entire year . This caused catastrophic flooding and the disaster resulted in more than 200 deaths, as well as billions of euros in damage.
Now, a new study led by a team from the Earth Sciences Department at the Barcelona Supercomputing Center – Centro Nacional de Supercomputación (BSC-CNS) helps to better understand why that episode was so extreme. The study concludes that the high temperatures of the Mediterranean Sea played a key role in the intensity of the rainfall, but adds a new element that had not been explored until now: the North Atlantic, which was also exceptionally warm at that time, contributed to greater moisture availability and more favourable conditions for the episode to develop with such intensity over Valencia. This is the first time that the role of the North Atlantic in the exceptional precipitation of this DANA has been evaluated.
To analyse how abnormally high sea temperatures influenced rainfall in Valencia, the BSC team used the MareNostrum 5 supercomputer to generate high-resolution simulations of the planet's atmosphere. Different scenarios were compared, contrasting the actual temperatures observed with those usual for that time of year. According to the study, precipitation on the day of the event would have been up to 40% lower if those unusually high sea surface temperatures had not been recorded in the Mediterranean and North Atlantic. In the specific case of the North Atlantic, its contribution increased the intensity of the episode by 15%.
The importance of the finding extends beyond explaining a specific case. The work reinforces a key idea: although the impacts of climate change manifest locally, the processes that trigger and fuel them can have a much broader reach. What happened in Valencia did not depend solely on local atmospheric conditions or the warming of the sea off its coast, but also on a broader oceanic context, connected on a regional and global scale.
“This work shows that, to understand why an extreme event becomes so devastating, it is not enough to look only at what is happening in the affected territory: the state of the ocean, even at a great distance, can make a decisive difference in the magnitude of the impact,” says Ramiro Saurral , lead author of the study and researcher at the BSC’s Climate Variability and Change group.
This approach is particularly relevant from a social perspective. A better understanding of how the ocean and atmosphere interact helps to improve the anticipation of extreme events with serious consequences for the population, infrastructure, mobility, emergency services, and land-use planning. In the context of climate change, having tools capable of representing these connections on a large scale will become increasingly important for assessing risks, providing early warnings, and designing more effective adaptation measures.
Initiatives such as the Climate Change Adaptation Digital Twin (Climate DT) of the European Destination Earth initiative point precisely in this direction. This system, in whose development the BSC plays a very prominent role, is designed to produce global climate simulations with great spatial and temporal detail, provide information on a planetary scale and enable scenario analysis and simulations of extreme phenomena such as the one that occurred in Valencia.
Francisco Doblas-Reyes , ICREA professor and director of the Earth Sciences Department at BSC, explains: “We need high-resolution global simulations because climate change is not the result of independent phenomena at the local scale. Tools such as Destination Earth's Climate Change Adaptation Digital Twin allow us to analyse how processes occurring on a planetary scale influence the formation, evolution, and intensity of climatic events experienced at a more local level.”
For BSC, this type of research reinforces the need to move towards simulation systems capable of capturing these connections and, thus, converting scientific knowledge into useful information to better protect society from climate extremes.
Diego Campos , a researcher at the BSC and co-author of the study, concludes: “Phenomena like this one remind us that extreme events are not just a meteorological issue: they have a direct impact on people's lives, safety, infrastructure, and the ability of communities to anticipate and respond.”
Reference :
Ramiro I. Saurral, Diego A. Campos, Katherine Grayson, Vladimir Lapin, Paloma Trascasa-Castro, Etienne Tourigny, Markus G. Donat, Stefano Materia, Eric Ferrer, Francisco J. Doblas-Reyes, “ The key role of Mediterranean and North Atlantic sea surface temperatures on the 2024 record-breaking Valencia precipitation event ”, Weather and Climate Extremes, Volume 52, 2026, 100877, https://doi.org/10.1016/j.wace.2026.100877 .
Weather and Climate Extremes
Computational simulation/modeling
The key role of Mediterranean and North Atlantic sea surface temperatures on the 2024 record-breaking Valencia precipitation event
27-Feb-2026
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.