The dry storm is once again at the center of meteorological news in Spain: Intense gusts and electrical activity without usable rain have favored very fast-moving fires, such as the one declared in the area of Tres Cantos (Madrid).
At the same time, this pattern leaves unusual postcards, such as sudden drops in temperature within minutes, the case of Valladolid, and a forecast that suggests that these episodes could be repeated in several inland areas of the peninsula in the coming days.
What is a dry storm and why is it a concern?
In a dry storm, clouds generate precipitation but this evaporates before reaching the ground by the low humidity and very warm air in the lower layers. The result is lightning and gusts of wind without effective rain, a scenario that can trigger the danger of fire.
The so-called frequently appear dry bursts: highly concentrated air descents that fall from convective clouds, causing sudden gusts that can be around 100 km/hThey do not provide water, they raise dust and they favor the spread of flames and material damage.
This type of storms is formed with dry and hot air at low and medium levels, something more common with prolonged heat waves, when the vegetation is most vulnerable and the mountain is very receptive to any spark.
The Tres Cantos fire: provisional assessment and key findings
The fire declared in the area of Tres Cantos evolved favorably during the early morning and could be perimeter, although it remains active with operational situation 2According to emergency services, it has already affected more than 1.000 hectares and forced the evacuation of about 180 people.
Initial research points to a dry storm as a source and propagation factor, with gusts exceeding 70 km/h who came to promote the front six kilometers in about 40 minutes, a development described as explosive by the authorities.
They have registered significant damage in the urbanization Soto de Viñuelas and were also affected Fresno Fountain and Ciudad del Campo (San Sebastián de los Reyes). In addition, the fire has reached several homes, awaiting full technical evaluation.
The accident left a fatality: a 50-year-old man with burns on 98% of the body, was taken by helicopter to La Paz Hospital, where he died. An 83-year-old man with chest pain was also treated.
The extinction has been played a role by the following: Firefighters of the Community of Madrid and forestry brigades with 26 fire trucks, three wet nurses, various drones y three excavators, plus 11 endowments of the Madrid City Council Fire Department, the EMU, Forest Agents, health resources (SUMMA112 and SAMUR), ERIVE, National Police, Civil Guard, Local Police and Civil Protection from different municipalities. aerial means They joined when visibility permitted.
In terms of roads, there were spot cuts as in the M-607, later reopened; the last report released did not include any information closed roads by the fire.
Valladolid: a sudden drop in temperature linked to a dry storm
An dry storm in the middle of the afternoon caused a drop close to 11 °C in a short time: the humidity rose from 14% to 37% as the mercury dropped after reaching 39,4 ° C at 16:00 p.m. For the following day, the forecast indicates about 34 ° C and a subsequent rebound with highs of up to 39 °C and minimums that could be around 22 ° C in the early morning.
Where these episodes can be repeated
According to AEMET, mostly storms are expected starting Thursday afternoon dry, in the peninsular interior, with special attention to Jaen y GranadaBetween Friday and the weekend, the phenomenon could extend to southeastneighbourhood, Pyreneesneighbourhood, Iberian System and sections of the Cantabrian mountain range; in mountain areas there could be some rain, but in general the predominant rains will be dry bursts at the center, on construction and also in Galicia.
The episode of heat is extended at least until the beginning of next week, a context that increases vulnerability of the mountains and facilitates rapid propagation when there is lightning and wind without effective precipitation.
Latent rays: the risk that cannot be seen
Los Ray associated with these storms do not always ignite the forest immediately. Sometimes the discharge remains latent in the trunk of a tree and combustion progresses slowly until, hours or days after, the fire emerges. Detecting them is difficult because they do not generate smoke previously visible.
This risk has been observed in different parts of the Iberian Peninsula and conditions surveillance after storms, as was verified in Alins (Lleida) with a lightning-related conatus. In episodes of dry storm, it is advisable to take shelter in closed and safe places to minimize exposure to discharges.
Combining dry storms, strong wind y dried plant fuel This explains the rapidity of the latest fires and requires extreme caution: reinforced extinguishing devices, attention to AEMET warnings and citizen collaboration are decisive while the heat persists and bursts and discharges multiply without rain.
