“A huge group of storms has formed”

The DANA (Isolated High Level Depression) of October 29, 2024 has already entered Spanish history. This is the worst rainstorm and flooding recorded in some areas of the Valencian Community since big “cold drops” of 1982 and 1987as reported by the National Meteorological Agency (Aemet) of Valencia. There are more than sixty deaths, following floods which reached the limits of the 500 liters per square meter in eight hours in cities like Chiva.

The special warnings issued by Aemet since the weekend already predicted that the situation would be catastrophic, with up to 200 l/m2. Portals like ElTiempo.es And Weatherized they increased their forecasts up to 250 or even 300 l/m2. Reality has exceeded -and even doubled in quantity and time- these estimates. The Valencian Association of Meteorology (Avamet) speaks of an “atrocity” with “historical” connotations with more 400 l/m2 in Cheste, Buñol or Torís. Requena reached 315 l/m2 and Utiel 275 l/m2.

Why were the forecasts late? He red notice of Aemet for the Valencian Community was issued on Tuesday morning: this is the maximum degree of danger due to bad weather, which is then transmitted to Civil defense. This is what happened on the night of Monday to Tuesday in the case of Valencia, when they were asked “not to leave their homes”. The climatologist Jorge Olcina declared in statements to EFE that “go put a warning and a “black” alert so that it is understood that life is in danger.

On social networks, Aemet wanted to deny the “hoax” according to which its radar in Valencia was not operational, specifying that it had been operational since Monday 28 “Aemet gives precipitation alerts”, he specifies. Ernesto Rodriguez Caminosenior state meteorologist and member of the Spanish Meteorological Association, in statements to Science Media Center. “If this precipitation then has more or less destructive effects, it will depend on the orography, the precipitation upstream, the location where the municipalities are located, the presence or not of obstacles…”.

In this sense, the Valencia Meteorological Agency highlighted that “floods are occurring in areas where it has barely rained”. As they explain, “highly swollen rivers, ravines and ravines” reach the coast while the mouth area experiences a “strong maritime storm that prevents normal drainage.” Thus, channel overflows occurred in towns like Utiel, and the Forata (Yátova) dam evacuated a flow 900 cubic meters per second after having to open the valves.

“Cluster storms”

“It has been a long time since there has been a situation of extremely heavy and torrential rain,” said the meteorologist. Francisco Martin Leon of Weatherized. “In some areas of Valencia, between 300 and 600 liters/m2 accumulated in 24 hours and, in some circumstances, 200-300 l/m2 fell in just 4-5 hours in some areas of the Valencian Community.” Behind this exceptional “cold drop” lies a scientific term that experts repeat today, the “Mesoscale convective systems‘.

This is the most destructive type of storm, the specialist explains to EL ESPAÑOL. “THE Marsh of All “The year 1982 was due to the first convective complex described in Europe,” he remembers. “A simple storm lasts 10 minutes, a deep storm lasts six to twelve hours, but these are large cluster storm groups who organize themselves to create a “multicellular organism”. When they reach “enormous proportions“as in this case, they are called”mesoscale convective complexes“.

If this is the most destructive typology of adverse phenomena as such, why does it not appear as such in Aemet’s forecast? No matter how much systems have improved, Martín León believes, forecasting cannot be “fine enough” to discern whether an estimate of “more than 200 l/m2” becomes “500 l/m2” for a specific location . However, underlines the meteorologist, even if Aemet was “conservative”, the red notice is the maximum and should have activated the most rigorous measures. However, it could have been activated days before.

“A ‘black level warning’ wouldn’t have changed anything. A forecast of 200 l/m2 is already scandalous“, he appreciates, emphasizing that measures such as the suspension of classes as Murcia did are appropriate to reduce traffic in these circumstances. The specialist hopes that the tragedy will serve as a “repellent” to improve the response to disasters. “Numerical models bring us closer to the reality of what will happen,” he concludes. if there is no predictor that interprets them and if appropriate measures are not taken, they are useless. Someone should to have come out to show one’s face, like in the United States“.