Wildfires of a scale not seen in living memory are burning through southwestern France and central Spain, and have together forced more than 300,000 people from their homes.
Market Context
In France’s Gironde region, a blaze that erupted near Saumos on July 22 has consumed more than 420 sq km of forest and scrubland — an area roughly four times the size of Paris — damaged or destroyed more than 240 homes, injured 80 firefighters, and come within 15km of the outskirts of Bordeaux.
In Spain, separate fires burning west and south of Madrid have scorched about 770 sqkm, an area larger than the capital itself. The fire in Ávila province, at roughly 500 sqkm, is now the largest in recorded Spanish history, the government has said.
French President Emmanuel Macron, visiting a crisis coordination centre near Bordeaux on Monday, called the situation France’s worst fire-related crisis since World War II. “We’re facing a completely unprecedented fire,” he said.
While calmer conditions on Monday allowed crews to halt the main fire’s advance, nobody is declaring victory yet. A fresh heatwave arrives in France on Tuesday and in Spain by Wednesday, threatening to undo the gains. “The weeks ahead will be hard. We must hold firm,” Macron said.
Nasa has called them the “fire-breathing dragon of clouds”, The Guardian reported.
Once formed, a pyroCb can amplify the disaster that created it.
Rising air pulls powerful winds towards the fire, and downdrafts punch gusts back to the surface. Those shifts can turn the flames, split them into several fronts, or send them racing in a new direction.
Lightning can also spark spot fires far beyond the main blaze, and the systems can even spin up whirling columns of flame.
Similar storms have been reported above California and neighbouring American states in 2021.
In Europe pyroCbs are uncommon. Portugal recorded one during its deadly 2017 fire season, and France has now joined the list.
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The immediate fuel for the Spain and France wildfires is a summer of successive heatwaves that arrived early and hit hard, drying out forests and scrubland across western Europe, with little rain since May.
Human activity supplies most of the sparks. French Prime Minister Sébastien Lecornu wrote on X that nine out of 10 fires are human-caused, most through carelessness — a cigarette butt, a barbecue, work carried out without precaution, Reuters reported.
In both Bordeaux and Ávila, among the worst struck areas, July’s high temperatures have averaged 32°C, almost 6 degrees above the 1961-1990 norm, the Reuters Climate Monitor reported.
Spanish officials have also classed some of the blazes as “sixth-generation” fires, the most extreme and uncontrollable category.
“What we’re experiencing isn’t a succession of isolated events. It’s the most painful expression of a climate emergency that is making sixth-generation wildfires more ferocious, heatwaves more frequent, and our territory more vulnerable,” Spanish Prime Minister Pedro Sánchez said.
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Officials have said the wildfires will likely burn for many weeks, and some could take months to fully extinguish.
Adding to that devastation is a looming heatwave.
Scientists say hotter, drier conditions give extreme fires more opportunity to spawn fire clouds and such storms, though long-term data is still too thin to establish a trend as yet.
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For firefighters, escape routes can close without warning as fresh outbreaks appear behind crews and equipment, sometimes forcing them to abandon direct attack and fall back to defend towns. The gravest danger, Giannaros said, is fire moving faster than evacuations can be organised.
PyroCbs have until now been essentially an Australian and North American phenomenon — Canada alone produced a record 142 in 2023.
During Australia’s 2019-2020 summer, fire officials in New South Wales reported embers from a pyroCb landing 30km ahead of the fire front, the BBC reported. That season, 33 people, including four firefighters, were killed, and more than 11 million hectares of bush, forest and parkland was burnt.
Future Forecast
Part of what has made these fires so destructive, and so hard to predict, is a phenomenon France has never recorded before: the fire generating its own thunderstorm.
On Friday evening, two days after the Gironde fire began, the departmental fire and rescue service confirmed that the blaze had produced a pyrocumulonimbus — a “fire cloud”, or pyroCb — a vast, electrified storm cloud created by the fire itself.
France’s national firefighters federation said the country had never documented one before.
The cloud generated lightning that struck the ground beyond the fire’s edge and ignited fresh blazes, along with violent, erratic winds that drove the flames in new directions. The Gironde fire chief, briefing Macron, described a fire unlike any his crews had tackled — “a fire that’s going everywhere”.
The cloud weakened overnight as humidity rose, then re-formed several times over subsequent days. In effect, the fire began making its own weather.
The mechanics are those of an ordinary thunderstorm, but one supercharged by flames.
“Imagine a campfire so large and hot that the smoke rising off it turns into a storm-like cloud,” Theodore M Giannaros, a fire meteorologist at the National Observatory of Athens, told AP. “That is a pyroCb — a storm cloud born from the intense heat that a wildfire produces.”
A sufficiently intense fire sends hot air, smoke and moisture surging upwards in a plume. As the plume climbs, it cools. Water vapour condenses around particles of ash, and once above the freezing level, droplets become ice crystals. Their collisions separate electrical charges, which can then cause lightning.
Giannaros said there’s no set temperature at which these clouds form. What they need is very hot, very dry air near the ground and cooler, moister air above.
These clouds are enormous and can reach altitudes of 10-15km and punch into the stratosphere.
“It’s a feedback loop, not a one-way effect,” Giannaros told AP. “Once it forms, the cloud becomes its own weather system, sitting on top of the fire and making it harder to predict.”
France’s weather office forecasts temperatures of 35°C and above in the southwest from Tuesday, rising towards 40°C with dry winds. Spain’s weather agency AEMET has announced the country’s fourth heatwave of the year from Wednesday, with temperatures of up to 42°C in the northeast, warning that fire danger will climb to extreme levels on high heat, gusty southerly winds and widespread low humidity.
“Today and tomorrow are absolutely crucial days in tackling this wildfire. From Wednesday onwards, weather forecasts become significantly more unfavourable,” Spanish interior minister Fernando Grande-Marlaska was quoted as saying by Reuters.
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Behind both sits the climate crisis. Europe is the fastest-warming continent, heating at roughly twice the global average since the 1980s, according to the EU’s Copernicus Climate Change Service and the World Meteorological Organization.
