Top News

Firefighters battling devastating fires in France have had to contend with a new threat: immense fire clouds that create their own wind and even lightning that can spark fresh blazes. 

Known as "fire clouds" or pyrocumulonimbus clouds, these ominous-looking thunderstorms are created by extreme wildfires and can exacerbate already extremely dangerous conditions.

This phenomenon, which is new to France, is yet another consequence of human-caused climate change, according to French researcher Jean-Baptiste Filippi, who studies wildfires.

Stay up to date with the latest news. Follow KT on WhatsApp Channels.

Clouds of smoke rise into the sky from a wildfire in France

As firefighters in southwest France struggle to bring a forest inferno under control before yet another heatwave descends on the country, Filippi told AFP about the phenomenon.

What is a fire cloud?

Filippi: It is a storm where a column of air forms above a fire.

It starts off as a cute little white cloud -- a cumulus cloud, which is formed because water vapour has turned into tiny droplets.

As the Sun heats the ground, the water vapour suddenly condenses. The cumulus becomes a much larger cloud, containing thousands of tonnes of suspended water. 

Then, when the surrounding air has become heated enough, it forms a column with an anvil-shaped cloud — the cumulonimbus.

This photograph shows beach towels on the beach of Moutchic in Lacanau, southwestern France on July 24, 2026, as clouds of smoke rise into the sky from a wildfire

This condenses even more air and generates more energy, with updrafts of more than 150 kilometres (90 miles) an hour.

It then rains, but the rain evaporates before it reaches the ground.

But it still cools the atmosphere where it falls, creating strong downdrafts.

Are fire clouds rare?

It is a common phenomenon in Portugal, California and Australia, where firefighters are more used to them. In Portugal, they had been rare until the deadly 2017 fires in Pedrogao Grande changed things. 

In France, pyrocumulonimbus clouds are quite new. There were some in Landiras south of Bordeaux in 2022, but not for long.

Therefore, we need to learn how to manage fires that creates their own wind — this is something relatively new.

A beachgoer walks in the ocean from the beach of Moutchic in Lacanau, southwestern France on July 24, 2026, as clouds of smoke rise into the sky from a wildfire

Is climate change to blame?

Yes, it is. A consequence of global warming is more frequent heatwaves. While thunderstorms are common in the region of this fire, thunderstorm conditions after three successive heatwaves is a new combination.

Are they predictable?

Weather services can predict thunderstorms. But because these storms are located directly above a fire, we would need to know the fire's exact location in advance. That's impossible. 

We can predict the conditions that will lead to these fires, but we won't know exactly where they are.

The biggest challenge is how unpredictable they are. The fire in France's southwest Gironde region started with northerly winds, then westerly, then southerly, then easterly, then back again to the south, then the west...

Beach goers sit on the beach of Moutchic in Lacanau, southwestern France on July 24, 2026, as clouds of smoke rise into the sky from a wildfire

On top of that, there is this potential energy in the atmosphere which meant that, locally, the convection column sucked up the embers and carried the fire further afield.

The local conditions became catastrophic and the rate of the fire's spread was staggering.

Blazes merge outside Madrid as tens of thousands flee fires in France Thousands flee deadly wildfires in Europe; Madrid declares national emergency 12 killed, 23 missing in one of Spain's deadliest wildfires