Maps. Satellite data and images show how the wind transformed the fires of Ávila and Madrid.

The largest wildfire in Spain's history erupted in the regions of Madrid and Ávila, consuming over 67,000 hectares of land in just a few days. The fire began near the village of Burgohondo in Ávila province and quickly spread due to extreme weather conditions, particularly high winds that shifted direction unexpectedly. This change in wind patterns caused two major fires, one in Ávila and another in Madrid, to converge, creating a massive blaze that threatened entire communities and forced evacuations. Satellite imagery and meteorological data have been crucial in understanding how the fire evolved and why its impact was so severe. Satellite monitoring systems such as NASA’s FIRMS project and the European Space Agency’s Copernicus program played a key role in tracking the fire’s progression. These technologies allowed experts to observe the initial outbreak, the expansion of the flames, and the influence of environmental factors, especially wind. Unlike other satellites that pass over the Earth only a few times per day, the fixed-position Meteosat satellites continuously monitored the area, capturing images of smoke plumes and tracking the movement of the fire in real time. This continuous surveillance revealed how the wind changed course, altering the trajectory of the fire dramatically. On Friday, the wind was blowing from the southwest, pushing the flames eastward from Burgohondo through heavily wooded areas. By Saturday morning, however, the wind had turned, shifting the fire’s direction toward the south, into the Tiétar Valley. This shift created a dangerous situation where the two main fronts, the one originating in Ávila and the one in Madrid, moved closer together, eventually merging near the San Juan reservoir. Emergency services had long feared this scenario because it would significantly increase the scale and intensity of the disaster. Meteorological records show that the wind speeds recorded on Friday were unusually high for the region, with gusts reaching levels that are rare for this time of year. Combined with low humidity and temperatures exceeding 30 degrees Celsius, these conditions created ideal conditions for rapid fire spread. Between Thursday night and Friday night alone, the fire doubled in size, growing from approximately 7,000 to more than 14,000 hectares, according to satellite measurements taken during that period. The fire continued to grow rapidly throughout the weekend, fueled by dense vegetation, including forests that made up nearly half of the burned area. The terrain itself contributed to the severity of the fire. Over 53 percent of the land consumed by the blaze consisted of forested areas, which burn more intensely and spread fire more quickly than open fields. Analysis of the affected zones using the EFFIS system and CORINE Land Cover maps showed that at least 35,000 hectares of forest were destroyed in the combined fires in Burgohondo and the Sierra Oeste region of Madrid. The presence of underbrush and dry vegetation further accelerated the fire’s advance, making containment efforts extremely challenging for firefighters. Emergency responders faced immense pressure as they worked to protect populated areas and prevent the fire from spreading further. Entire villages were evacuated as the flames approached, and the threat to infrastructure and human life remained high throughout the crisis. Firefighters used aerial support and ground crews to create firebreaks and suppress the flames, but the sheer scale of the fire overwhelmed local resources, necessitating assistance from national and international firefighting teams. As the fire continues to burn, authorities remain focused on containing the remaining hotspots and preventing new outbreaks. The incident has raised concerns about climate change and the increasing frequency of extreme weather events that contribute to large-scale wildfires. Scientists and officials are reviewing the meteorological data and fire behavior models to better understand the circumstances that led to this unprecedented disaster and to improve preparedness for future incidents.