Suddenly, a drought. In a few weeks, extreme heat has dried vegetation and suveraged soil humidity, generating a huge risk of large simultaneous fires. A Flash drought It is behind the fires that burn multiple areas of Spain, as experts analyze.
The flash droughta sudden drought, “has turned the vegetation into fuel, that is, it has increased the propensity of the vegetation to burn with high intensity and propagation speed,” explains the Professor of Regional Geographic Analysis Cristina Montiel.
This fast desiccation – in contrast to droughts classic that develop progressively – is caused by “the impact that heat outside the records has on the plants and on the ground” – Montiel's. That makes the water evaporate from plants and the terrain, because the more heat it makes, the more capacity the atmosphere of absorbing moisture and drying the environment has.
“The trigger of this type of drought events responds both to strong precipitation deficits and to anomalous increases in evaporative demand by the atmosphere”, According to this research from the University of Zaragoza (Unizar). In other words, it is not only that it has not rained, but that the extreme heat has been taken suddenly the moisture there was already.
In this way, “in the dry regions (limited in water) of the center and southern Spain, the evaporative demand of the atmosphere plays an essential role in the trigger of the sudden drought during the warm station,” the Unizar thesis ends.
The Iberian Peninsula experiences a wave of intense and prolonged heat since the month of August began, that is, he chains days and days with temperatures much higher than those expected at this point of the year – when they are already very warm in itself.
The data accumulated by the AEMET illustrate to what extent Spain is dry these days. The evapotranspiration map shows high levels extended by Spain between July 30 and August 5. The situation, far from relieving, has worsened later.
And if you look at the Moisture map of the soil in its superficial layer For that August 5 (last available data) it is proven how almost the entire territory is “very dry” (between 0% and 10% moisture).
The heat wave of August has arrived after last June was the hottest June measured in Spain. On the peninsula the average temperature was 3.6ºC above average. “Extremely warm,” the Aemet described. It was also dry in the Peninsula and the Canary Islands and extremely dry in the Balearic Islands.
Then, Julio had “warm character” because, although the end of the month was colder than usual, “the abnormal heat of the first two weeks has had more weight in the monthly balance,” explained the Aemet. And if in the east peninsular there were abundant rains, “in the rest there were few rains.”
“The impacts of sudden droughts can be more severe due to their potential to increase forest fires,” he describes This analysis of the phenomenon published in Nature. And in addition, “they are increasingly common,” another study on how the world is concluded evolving towards sudden droughts In a context of climate change: “The transition is associated with amplified anomalies in evapotranspiration and the rainfall deficit caused by climate change caused by human beings.”
The relationship between flash droughts And forest fires are almost at the very origin of the description of this phenomenon. In fact, it has been established that a sudden drought in 2017 that crossed the great plains of the US and Praderas de Canada derived from 1.9 million hectares.
So this episode of sudden drought has impacted the Peninsula despite the fact that this year's global rainfall makes no water drought. “You have to be very alert,” says Professor Montiel.
And once the terrain and the plants have resected, the winds and the dry storms consume the necessary meteorological scenario to fire large forest fires in different locations. When a spark appears, this Molotov cocktail burns. And as Cristina Montiel emphasizes, “it is what is happening.”
The consequence is that a year that painted benign in terms of burned surface until May is accumulating carbonized hectares based on large fires. At the moment, at least 69,000 hectares of forest land affected by the flames.
The fire that burned the world heritage of the medulla in León has copied headlines, but since the flames destroyed that place, a fire in the Madrid town of Tres Cantos has cost the life of a person in addition to razing more than 1,500 hectares (which is another great fire for the list), another sinister forced to dislodge the Atlanter urbanization near the tariff High speed with Galicia. 5,000 people were evacuated in southern León for the fire that came from Zamora. The multiplication of spotlights made this Tuesday, the Ministry of Interior decreed the pre -emergency phase, in operational situation 1, of the State General Emergency Plan.
