The fire that started in the district of Coimbra and spread to the districts of Castelo Branco and Guarda has already consumed approximately 60,000 hectares, a fire expert and member of the technical committees analysing the major fires of 2017 told Lusa news agency.

The researcher from the University of Trás-os-Montes and Alto Douro (UTAD) noted that the largest fire recorded in Portugal was the one that started in Vilarinho, in the municipality of Lousã, in October 2017, which affected 53,000 hectares, followed by the fire in Arganil, also that year, with approximately 38,000 hectares (excluding this year's fires).

The estimate by the researcher from the University of Trás-os-Montes and Alto Douro (UTAD) is based on information from remote sensing fire monitoring.

The area calculated by Paulo Fernandes is larger than the provisional data from the Forest Fire Information Management System (SGIF), which indicates a burned area of 47,000 hectares (as of Tuesday), and from the European Forest Fire Information System (EFFIS), which records 57,596 hectares, with the latest update made today.

"It will most likely be the largest fire ever," the researcher emphasized, noting that some fires "are born to be large," considering that the Arganil fire, which started a week ago, "is one of those cases."

According to the researcher, the fire started in the early morning hours, following two lightning strikes on a ridge, which led to a slower response and the lack of the possibility of using aerial resources in the initial attack, "in a relatively inaccessible location."

In a thunderstorm environment that generates winds, the fire "spread very quickly" in the first few hours, he noted, considering this "a recipe for it to become a larger fire in the following hours or even days."

All of this, he noted, occurred in a "very complex territory," not only due to accessibility, but also due to the effect that topography "has on the evolution of the fire," in a region that burns repeatedly, recording major fires in 1987, 2005, and 2017.

"We know that the occurrence of large fires fosters larger fires in the future, because it makes the landscape increasingly homogeneous, and when the vegetation recovers, it grows simultaneously, and we will have an increasingly homogeneous continuum of vegetation—and if there's one thing fires like, it's this homogeneity," he explained.

According to Paulo Fernandes, the fire that started in Arganil is a convective fire, "very energy-dominated" and where there is little influence from wind.

After the storm, this fire spread "slowly in all directions," pointing to the rounded shape it assumed as it progressed.

"These fires occur when we have a lot of vegetation, with a relatively unstable atmosphere, where wind isn't really necessary and the fire doesn't have those very quick and sudden starts. Instead, it grows consistently over time, with a lot of dry biomass and, therefore, is very difficult to fight," he explained.