The scale of the tragedy that occurred Tuesday evening in the province of Valencia has few precedents. Although there is a certain level of uncertainty in climate phenomena and no one imagined how DANA would impact so many municipalities in this way, there are factors that explain why it targeted certain areas.
There is already more than 90 dead and many missingmany roads and railways remain closed and some towns continue to have difficulty restoring communications.
The effects of this DANA, the most catastrophic in this century, are reminiscent of those of Hurricane Milton in Florida. But, as the NGO Ecologistas en Acción points out, while in Tampa there were 0.73 deaths per million inhabitants (a total of 23), in Valencia more than 13 were recorded.
The epicenter of the tragedy was the municipality of Paiportawhere more than half of the deaths are concentrated. Neighboring towns like Massanassa, Torrent and Alfafar, in the Valencia metropolitan area, were also affected, as well as inland towns like Chiva, Cheste or Utiel.
Outside the province, deaths were recorded in the towns of Mira (Cuenca), Letur (Albacete) and Álora (Málaga).
Different types of factors combine in the tragedy caused by DANA. Some are intrinsic to this type of weather phenomena; others are linked to the characteristics of the most affected areas; Finally, the current climate framework favors – and will continue to do so – events of this intensity.
Physical characteristics of the region
The province of Valencia has already experienced catastrophic episodes of DANA (isolated depression at high levels, formerly known as cold weather). In 2019, there were six deaths. In 1987, two people died and in 1982, eight.
The worst episode in memory occurred in 1957, known as the “gran riuà”, which left 81 people dead. To prevent this from happening again, Plan Sur was launched, diverting the course of the Turia from the center of the Valencian capital to the south.
This river and the Júcar have a high potential for flooding, as they are areas close to the coast with a low slope, which causes their overflows to flood large areas. This is why various pipeline projects have been carried out.
Paiporta, Torrent and other affected towns are south of the new Turia canal. But it was the overflowing of the ravines, and not that of the river – the canal which diverted it is capable of evacuating 5,000 cubic meters of water per second – which caused these tragic floods.
“There have been other boulevards that are just parallel to the new Turia canal,” he explains to EL ESPAÑOL Andres Diezof the Mining Geological Institute. “There is the Rambla del Hoyo and others that They have long been known to cause problemsThere are even studies on this subject.
In the case of the Júcar, it was a tributary, the Magro river, which overflowed, affecting the municipalities of Utiel, Carlet and Algemesí. “Contrary to other episodes, the heavy rains were not concentrated on the coast but between the coasts and the mountainous areas,” he explains. Samuel BienerWeather forecaster.
“Precisely, the valleys and mountains most exposed to these southeast flows are those where such intense precipitation occurs, associated with convective trains or systems that tend to develop in the more unstable areas of the DANA, where the most intense precipitation occurred.”
Stability and convection trains
DANAs are common at this time of year, where there is a clash between polar air arriving from northern Europe and warmer, humid air from the Mediterranean.
One of the keys to this episode was the stability of the DANA, which remained immobile for a long time, dumping all the water in very specific areas.
“The very constant and humid easterly flow affected the mountain ranges close to the coast, providing significant energy for storm development, and the situation remained stable for more than 12 hours,” he explains. Mar Gomezhead of meteorology at eltiempo.es.
These storms were limited around a line of instability, what we call convective trains. Actually, a straight line can be drawn between the most affected nucleifrom Utiel, near the province of Cuenca, to Alfafar, passing through Cheste and Torrent.
In other words, the storms were focused on very specific points for a long period of time. But there’s one final factor missing that explains why so much water has accumulated to be dumped in the same area for so long.
In its X account, the State Meteorological Agency described this episode of torrential convective trains as “catastrophic”, the most harmful of the century in the Valencian Community.
Climate change and the tropical sea
The Mediterranean recorded record temperatures in 2024. On August 15, the highest record was observed, of 28.47 degrees, according to the Copernicus service, the European Union’s Earth observation program.
In fact, the 20 highest daily values ever recorded in this sea date back to the last decade; almost everything, over the last two years.
Even today, at the end of October, “the temperature of the Mediterranean is about 2 to 2.5 degrees higher than usual at this time of year, so we have top-notch gasoline”, explains meteorologist Samuel Biener.
With higher temperature comes higher humidity, warm air is able to hold more moisture, which it will eventually release later. This explains the rainfall which reaches almost 500 liters per square meter in just eight hours in cities like Chiva.
Mar Gómez recalls that this tropical Mediterranean is the product of the gradual increase in temperatures caused by the consumption of fossil fuels and the expulsion of gases like CO2 into the atmosphere.
“We have an increasingly warm Mediterranean, whose temperature increases every year and contributes, with this humidity factor, to more intense rains. Warmer air admits a higher water vapor content and, therefore, more humiditycontributing to torrential rains.
The corollary of this perfect storm is that this unusual phenomenon will become more frequent and have greater intensity. “These episodes have had a return period of several decades, but in recent years we are seeing them becoming more frequent,” warns Biener.
The factors are there. It now remains for the authorities to take this into account.
