Pyrocumulonimbus clouds, massive storm systems generated by intense wildfires, are playing a significant role in the recent surge of wildfire activity across Europe, experts say. These “fire clouds” form when the heat and energy from a wildfire cause smoke plumes to rise rapidly, cooling and condensing moisture at higher altitudes to create towering storm clouds that can reach up to 15 kilometers (nine miles) high and penetrate the stratosphere.

Rick McRae, of the University of New South Wales’s bushfire research group, described these clouds as thunderstorms born from fire plumes. The pyrocumulonimbus clouds can cover up to 10,000 cubic kilometers of atmosphere and produce strong winds and lightning, which can exacerbate wildfire spread by igniting new blazes and creating unpredictable fire behavior. McRae noted that the presence of such clouds signals extreme danger and often necessitates widespread evacuations.

While Australia has documented pyrocumulonimbus clouds since the early 2000s, their occurrence appears to be increasing globally. Recent observations suggest that France may be witnessing these phenomena for the first time, reflecting the growing threat posed by extreme wildfires in Europe.

The heightened frequency and intensity of these fire clouds are linked to climate change, which has altered atmospheric conditions, surface weather, and vegetation dryness, increasing the likelihood of extreme fires. The combination of successive heatwaves, record-breaking temperatures, and prolonged drought has left vast areas of Europe’s forests and grasslands tinder-dry, creating ideal conditions for large-scale wildfires.

This summer, several European countries have struggled to contain fires amid heatwaves that officials warn are becoming the new normal. France, Spain, Greece, and Italy have faced particularly severe outbreaks. Spain’s prime minister, Pedro Sánchez, described the wildfires as “the most painful manifestation” of the climate emergency, emphasizing that these events are no longer exceptions but expected outcomes of warming conditions.

The European Commission has acknowledged that Europe is currently ill-prepared for the escalating impacts of the climate crisis. Teresa Ribera, the Commission’s lead on the green transition, indicated plans for a comprehensive adaptation strategy scheduled for release in October, aiming to address shortcomings in current policies.

The scale of the wildfires has prompted cross-border cooperation within the European Union. The Commission has coordinated the deployment of seven firefighting planes and four helicopters to France, alongside six planes and three ground teams sent to Spain, following these countries’ activation of the EU’s emergency assistance mechanism. Additional personnel have been dispatched to support efforts in the Bordeaux region.

Firefighters continue to confront rapidly advancing fires, with one recent blaze in southern Spain reportedly spreading at speeds up to 6 kilometers per hour—far outpacing the usual reaction capacity of ground crews, who typically manage fires advancing at a few hundred meters per hour. Italy has also sent firefighting equipment and teams to assist neighboring countries while simultaneously contending with its own outbreaks. In southern Italy, over 400 individuals, many tourists, were evacuated by sea from the Gargano peninsula as flames approached coastal areas, and dozens more were moved from homes in Basilicata.

The widespread fires have caused a significant deterioration in air quality across large parts of southwestern France, prompting health officials to issue warnings. Vulnerable groups, including the elderly, pregnant women, and those with respiratory or chronic conditions, are advised to take precautions such as closing windows, wearing FFP2 masks outdoors, and avoiding strenuous activity. Authorities have distributed over 1.5 million FFP2 masks in affected regions.

Forecasters caution that another intense heatwave could strike France imminently, with temperatures expected to reach 40 degrees Celsius in some areas, raising concerns about the ongoing wildfire threat as the continent faces an extended fire season lasting potentially until early November.