When we see the infrared images taken by the company Maxar from the satellite, it is hard to believe what we are seeing: the town of Altadena, in California, is almost completely burning and every red dot on the map is a house on fire. It is one of the fires that have surrounded the city of Los Angeles in recent days and that has cost the lives of at least a dozen people, in what is on its way to becoming the most destructive fire in the history of the United States. .
The tragedy is due to a combination of factors: hurricane-force Santa Ana windsthe drought for months and the lack of troops and resources. But it is also an example, according to experts, of a new type of fire that affects the outskirts of many cities and that is increasingly frequent, not only in California.
“We knew that if it started, nothing could stop it,” he says. Joaquin Ramirezhead of the technology company Technosylva, which works for the Government of California in fire prevention. “In the entire area we had an initial attack rate at level 5, which is the maximum on the scale, which means that there are no possible means to combat it.”
According to the expert, if a fire breaks out in these circumstances, when winds of 120 km/h blow down the slopes of the mountain, the teams cannot stop it directly and have to dedicate themselves to evacuating populated areas. “Added to this is the number of steep mountainous areas that surround Los Angeles, which make the fire inaccessible,” he points out.
New areas, new fuels
Another of the main factors, for Ramírez, is the way in which this region of California has been urbanized. “Cities are burning because American houses have historically been built of wood, due to availability and low price,” he explains. In this area the fear of earthquakes is greater than the fear of fires, and wood is more resistant to earthquakes than concrete and cheaper to rebuild, he adds.
The second factor is that, as the urban area has expanded so much, the houses are too close to the forests. “They are areas in the urban-forest interface,” he says. “And, if you put the houses in the mountains, you have to clean it, or you have to have ecosystems that dampen the fire, as we have done in Spain with the pastures.”
This human development in fire-prone regions, where neighborhoods intersect with forest and grassland vegetation, has introduced new, highly flammable fuels, he notes. Virginia Iglesiasa researcher at the University of Colorado at Boulder, in an article in The Conversation. “Buildings, vehicles and infrastructure tend to catch fire easily and burn at a higher temperature and speed than natural vegetation,” he writes. These changes have significantly altered fuel patterns“, creating conditions conducive to more serious and difficult to control forest fires.”
As the urban area has expanded so much, the houses are too close to the forests: they are areas in the urban-forest interface
Joaquin Ramirez
— Fire expert and head of the technology company Technosylva
Fires caused by people usually occur in or near populated areas, where flammable structures and vegetation create even more dangerous conditions, the researcher recalls in her article. As urban development expands into wild areasincreases the likelihood of arson and properties potentially exposed to fire, creating a vicious cycle of increasing wildfire risk.
Maps of flammable areas
Victor Resco of Godprofessor of forest fires and global change at the University of Lleida, assures that these types of fires that occur in areas where the density of houses is between low and intermediate are already occurring in other areas of the world. “We saw it in the 2018 fires in AtticaGreece, where there were more than a hundred deaths in an urban transition zone,” he explains to elDiario.es. “It has happened in Australia, in Portugal and I could perfectly spend any summer in Barcelona with the Collserola Natural Park”.
Whenever there are houses and forest together we are likely to have a catastrophe. We need to make a map of flammable areas as those of undoubtable areas are made.
Victor Resco of God
— Professor of forest fires and global change at the University of Lleida
Although in Catalonia there is a rule that requires leaving 25 meters of distance between any urbanized area and vegetation areas, this is a clearly insufficient measure, in the opinion of Resco de Dios. “In these fires, the winds carry the embers several kilometers away.” What is already being discussed is the creation of green areas that act as firebreaks, but in his opinion the big problem is the way in which we plan and organize the territory.
“As long as there are houses and forest together we are likely to have a catastrophe,” he says. “We need to make a map of flammable areas like those of flood zones are made, because many people live in a mousetrap and don’t know it.”
Too close to the trees
Resco de Dios and his team have just finished a studyawaiting review, in which they show greater exposure to fire risk for the population living on the periphery of protected forest areas. Based on the analysis of more than 10,000 protected forest areas in Europe, California, Chile and Australia, they conclude that the population on the periphery of these forest areas is up to 16 times more likely to be exposed to large forest fires. And, having expanded inhabited areas horizontally, many of these areas are densely populated.
Buildings, vehicles and infrastructure tend to catch fire easily and burn at a higher temperature and speed than natural vegetation.
Virginia Iglesias
— Researcher at the University of Colorado at Boulder
“One of the main problems, on many occasions, is not that we have gotten into the forest, but that the forest has gotten into us,” explains the expert. Knowing if your house or the campsite where you are going to stay is built within one of these fire zones is relevant information, in his opinion, to which we should start paying more attention, in view of the increase in episodes. extremes and megafires.
“The areas around Barcelona are the ones that are most at risk because it is where there is the highest population density,” he points out. “But this is a problem that is quite common throughout our geography: we are experiencing it in 2022 with the evacuations in Galicia or with the fire in the Sierra de la Culebrain Zamora.” The scale of these fires will never be as large as that of California, he admits, but many of these transition zones between forest and city, like those along the entire Mediterranean coast, have all the ingredients for a similar catastrophe. “And we should start taking preventive measures as soon as possible,” he concludes.
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