“The AEMET did not warn in the morning” or ‘If a radar was unable to detect the deadly Dana, it can be said that it did not work’ (sic). This type of message has been circulating, accusing the Spanish State Meteorological Agency (AEMET) of not predicting the arrival of the DANA (the Spanish acronym for high-altitude isolated depression) and the floods that hit Valencia on October 29. Others claim that the meteorological radar for the province of Valencia was unable to ‘detect’ the storm that would pass through the region. It is also claimed that the "French AEMET" did detect the DANA phenomenon in Valencia and eastern regions of Spain, while the Spanish one did not.
This is disinformation:
A radar does not ‘detect’, a radar collects data in real time which is then processed by computers, together with data from other sources, to make a weather forecast for the following days
According to AEMET, this radar had been out of order since September 2023 and was operational again on 28 October 2024 (one day before the worst rainy day) thanks to an alternative power supply.
Both in the days prior to 28 October and afterwards, the AEMET predicted, warned and informed about the DANA because its prediction is independent of that particular radar and is also fed by other data.
Météo-France, the equivalent agency in France to the Spanish AEMET, does not make predictions beyond its borders. However, a French meteorological populariser who does not work in the field of meteorology and has no connection with Météo-France did posted an alert on X on the morning of the same day as the storm.
The AEMET did predict the DANA phenomenon in Valencia and eastern regions of Spain
As we have reported in Maldita.es, the AEMET predicted the formation of a DANA phenomenon in Valencia and eastern regions of Spain on Wednesday 23 October and warned of its arrival on the peninsula in a first information note on Friday 25 October, four days before the torrential rains on Tuesday 29 October. It then went on to clarify the forecast. Therefore, in addition to what we explained above, the prediction of the DANA phenomenon in Valencia and eastern regions of Spain by the AEMET took place independently of the weather radar in the province of Valencia.
The radar does not predict the weather, it collects data
A weather radar is a device that makes it possible to locate precipitation or calculate its trajectory, i.e. where or how much it rains. The AEMET clarifies that it is ‘a weather monitoring tool, not a prediction tool. The forecast would have been the same whether the radar worked or not’. Numerical models are used to predict the weather and other adverse meteorological phenomena.
How do these models work? Taking into account some initial parameters (obtained from radar, but also from other resources such as satellite images) from different points in the atmosphere, a series of statistical operations and equations are carried out to estimate what the weather will be like over the next few days. The results of these equations are probabilities, i.e. there is always an uncertainty that increases the further the weather moves away from the date we want to predict.
‘We cannot treat meteorology as an exact science because when we make weather forecasts we work with probabilities,’ explained physicist and climate change meteorologist Isabel Moreno to Maldita.es in an article explaining why it is not correct to say that weather models failed to predict the DANA that affected southern Madrid and northern Toledo in September 2023. ‘What we do is solve the equations of the meteorological models a lot of times and with that we see what the most likely scenario is’.
Added to this uncertainty in any prediction is the fact that DANAs and storms are some of the ‘most complicated phenomena to predict’, as the AEMET indicated to Maldita.es in the same article.
The radar was operational from 28 October
In addition, the AEMET radar for the province of Valencia was ‘working since the morning of 28 October without interruption’ thanks to an alternative energy source. As we have already told Maldita.es, one of the hoaxes shared during this event is that this radar did not work during the storm, but was active from the day before the torrential rains of Tuesday 29 October.
It is therefore a piece of disinformation that the rain radar did not ‘detect’ the DANA phenomenon in Valencia and eastern regions of Spain: the phenomenon was predicted and the radar does not make weather forecasts.
The "French AEMET" did not predict the DANA phenomenon in Valencia and eastern regions of Spain
‘The French Aemet did predict the tragedy in Valencia that the Spanish one minimised: ‘400 l/m² and mortal risk’. This is one of the contents of the report that Météo-France, the French state meteorological agency, predicted up to 400 litres per square metre of rain in the province of Valencia. But it is a hoax: Météo-France did not predict anything in Spain and the 400 l/m² was predicted by a French weather forecaster who does not work for Météo-France. He did it after AEMET issued a red warning.
AEMET did not predict 180 mm of rain: it was a 12-hour minimum, not a maximum for the day
The contents that assure that Météo-France did warn about the DANA phenomenon in Valencia and eastern regions of Spain also accuse the AEMET of falling short in its forecasts about the rain that was going to fall. Both contents state that the AEMET predicted between 150 and 180 mm, less than half of the final accumulated rainfall. But this is also false. The red warning for Valencia, the maximum level that exists, implies a minimum of 90 mm in one hour or 180 mm in 12 hours. In fact, the special warning on Tuesday 29 October at 14:30 warned that it could ‘locally exceed 150-180 mm in 12-24 hours’. In other words, 150-180 mm in 12-24 hours was a minimum, not the maximum that could be reached.
‘The warnings are based on threshold exceedances. The red warning was issued because it was expected to exceed 180 mm in 12 hours. From that point on, it doesn't matter whether it was 181 mm or the almost 700 that it probably was, even if the magnitude of the tragedy is greater. With a red warning, all necessary measures must be taken to ensure that the population is exposed to extreme danger, which is what a red warning means,’ says AEMET spokesman Rubén del Campo: ’Red warnings in the event of rain are so rare that they should be used to paralyse normal life and get to a safe place.
Emergency situations are a favourable situation for the emergence of hoaxes. Thus, at Maldita.es we continue to debunk hoaxes and disinformation related to the DANA phenomenon in Valencia and eastern regions of Spainand various conspiracy theories since last Tuesday 29 October. It is essential: trust only official sources and, when in doubt, it is preferable not to share them. Here you can consult tools and sources for information on the DANA phenomenon that is sweeping across Spain.
