2024-10-30 19:43:00
“I have rarely seen a system like the one that formed yesterday. The storm was absolutely enormous,” summarizes Mar Gómez, meteorologist at eltiempo.esTHE DANA which in just a few hours devastated the Valencian Community and the areas of Castilla-La Mancha and Andalusia, causing the death of dozens of people.
An “unusually static” storm which, according to the expert, “is more typical of other regions of the planet, such as the United States, for example, than of our country”.
What happened in the atmosphere to cause a flood of this magnitude? According to Mar Gómez, a series of factors combined. “In the situation we experienced, the static position of DANA e contribution of humidity from the Mediterranean with the Levante wind and the still warm waters of the Mediterranean Sea. All this, combined with the orography and territorial planning, determines the dramatic situation we have experienced”, he summarizes.
And, as Gómez recalls, “the intensity of rainfall in this region allows, preliminarily, to place it as one of the worst events after 1982 (when the so-called Tous swamp occurred) and 1987”. In the episode we are experiencing these days, “the greatest accumulations were recorded in the Requena-Utiel area and in the entire northern and central area of Valencia, without counting the coastal strip”. Those accumulated, the details, “they reached 491 millimeters in Chiva, according to the Júcar Hydrographic Confederation, and 415.6 mm in the Buseo basin.” Rain gauges from other networks also report very high values. In Pedralba, for example, the AVAMET network recorded 394 mm. In Turís, this same network of stations recorded 325.2 mm.
“A large amount of this rain was collected in just a few hours. In the case of Chiva, for example, the amount accumulated was around eight hours, so we are talking about a very notable torrential nature,” says Gómez.
Precipitation accumulations therefore exceeded 400 mm, even approaching 500 mm. “All this represents the largest accumulation in 24 hours in the Valencian Community since 1996, when 520 mm were recorded in Tavernes de Valldigna.”
Weather forecast
The weather forecast already indicated it”DANA had the potential to cause very severe weather. Its position, its depth and the contribution of a high content of precipitable water have favored the high potential for intense rainfall”, explains the meteorologist. In the specific case of Valencia, the most affected area, “the establishment of a The constant flow of the Levant had an impact on the mountains near the coast, providing constant energy for the development of storms. “While this situation remained stable, for more than 12 hours, storm cores steadily developed in the same area.”
These storms have also acquired a high level of organization. It formed what meteorologists call “a mesoscale convective system, with embedded supercellular storms, which caused very persistent heavy rain, as well as some tornadoes,” Mar Gómez says.
An ‘exceptional’ episode
For his part, José Miguel Viñas, meteorologist from Meteordoes not hesitate to define this episode as “exceptional”, not only for what happened in the province of Valencia, but also in other areas of our country. “A particularity of this DANA is that, even if we have a history of very heavy rainfall, especially in the Mediterranean, It caused very heavy rainfall even within the peninsula. This tells us that it is no longer just the Mediterranean factor and elements such as hot water that can trigger very intense episodes of rain at this time of year. We are seeing that there may be other factors at play,” he analyzes.
In this sense, the meteorologist states that the intensity of the phenomenon “partly surprised him and partly not”. The forecast models “already indicated extreme rainfall throughout the Valencian Community, but I was surprised that they were concentrated in the interior of Valencia. It is not yet in our power to predict what will happen on a more local scale many hours in advance. And that is the challenge, to improve the forecast to be able to warn earlier,” he reflects.
Currently, he explains “Storm phenomena have extra energy and become very extreme. In Valencia, in addition to the heavy rain, in some areas there were also tornadoes and hailstorms of impressive size,” he says.
This episode was also influenced by a factor closely linked to climate change: the temperature of the sea water, which on the Valencian coast was one or two degrees higher than the average for this period of the year. “It’s not as significant an anomaly as other times of the year, but it has definitely contributed to more rain,” he says.
Another factor that influenced is the geographical area in which it occurred, since that area of the Gulf of Cadiz or Northern Morocco is quite critical for the formation of these DANA. “A storm is generated that gives rise to those humid eastern winds and triggers those stormy episodes that we have seen.”
The local scope of phenomena such as DANA makes it clear that they are much more difficult to predict. of heat waves, making it difficult to give warnings hours in advance.
Although the worst situation occurred in the Valencian Community, significant accumulations also occurred in the rest of the country: “In areas of Malaga, where the red alert was also activated, 175 mm were recorded in Álora, according to Aemet. There are other data from the area where the amounts exceed 200 mm, in the secondary networks, the rainfall was also notable in Mira (Cuenca), with almost 168 mm, in Dólar (Granada), with 157 mm or in the Fuensanta Basin (; Yeste, Albacete), with almost 150 mm, and very close to Letur”, summarizes Mar Gómez.
The forecast for the next few days
What awaits us in the next few hours? According to the meteorologist, on Wednesday, the impact of DANA will have two peaks. On the one hand “we will have very intense rain and thunderstorms in the north-east of the peninsula and on the other in the south-west. The yellow and orange alert for intense rain in the next few hours also extends to these regions”.
“The line of storms with which we started the day around the Iberian system will continue to advance towards the north-east. In the next few hours we expect heavy rains in La Rioja, southern Navarra, Aragon, much of Catalonia and they will continue in Castellón. The strongest they are expected around Teruel, south of Zaragoza, in the hinterland of Castellón and throughout the afternoon in points of the Catalan coast”, he specifies. On Wednesday afternoon, rainfall is expected to decrease, although it will persist in some areas: in Castellón, Tarragona, Girona and other places on the Catalan coast the rains will continue.
The other area affected by DANA will be the south-west of the peninsula: “We started the day with rain also in the western part of Andalusia: Huelva, Seville, Málaga and Cadiz mainly. In the next few hours the precipitation could intensify in those provinces. and, furthermore, “They will extend to the south of Extremadura, without excluding them in the south-west of Castile-La Mancha. The heaviest rainfall could occur in the Cadiz countryside and in the Grazalema mountain range.”
DANA will advance north and could fly over Portugal between Thursday and Friday. “The easterly winds will continue on the east of the peninsula, so we still expect rains in the Mediterranean, even if they will no longer be so intense. On Thursday they could still be strong in Castellón and Tarragona, without excluding them in Mallorca. On both days the rains will continue to occur in the south-west of the peninsula, especially in the west of Andalusia, Castilla-La Mancha and Extremadura.”
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The Catalan coast. As the situation develops, weather alerts remain in place, and residents in the affected areas are advised to stay informed about changing conditions and to follow the guidance of local authorities.
Meteorologists emphasize that the unusual intensity and distribution of rainfall during this DANA episode highlight significant changes in weather patterns, which may be influenced by climate change factors. The increased sea surface temperatures and atmospheric instability are exacerbating the severity of storm events, necessitating ongoing research to improve forecasting accuracy.
As rain continues to fall and river levels rise, communities in the hardest-hit areas are bracing for potential flooding and taking precautions to mitigate damage. Emergency services are on alert, ready to respond to flooding incidents, and towns are implementing safety measures to protect residents and property.
this exceptional meteorological phenomenon serves as a reminder of the importance of preparedness and resilience in facing increasingly extreme weather events.