France’s First Fire-Cloud: What It Means for Wildfires and the Economy
Understanding the Impact of Pyrocumulonimbus on France and Its Economy
By Coralie Lamarque
July 28 (Reuters) - France is grappling with an unprecedented fire season that has led to the evacuation of hundreds of thousands of people and dealt a blow to the economy during the peak tourist season.
But it's not just the scale of the fires that is breaking new ground. They are also behaving in ways not seen before in France, including the formation of the country's first-ever reported pyrocumulonimbus, or "fire-cloud".
Below is a look at this rare phenomenon:
What Is a 'Fire-Cloud'?
Definition and Formation
A pyrocumulonimbus is a cloud that forms above a large wildfire when intense heat drives smoke, ash and water vapour high into the atmosphere.
"You can think of it as like a chimney, which is a fire at the bottom and the smoke going straight up a chimney into the stratosphere," David Bowman, professor of pyrogeography and fire science at the University of Tasmania, told Reuters.
Predicting Fire-Clouds
While meteorologists can identify conditions that favour their formation, they cannot predict with precision when or where a fire-cloud will develop, said Jean-Christophe Vincendon, wildfire coordinator for the French national meteorological service.
How Do They Worsen Wildfires?
Increased Danger and Unpredictability
Fire-clouds can make wildfires more dangerous and less predictable by generating powerful winds that alter a fire's direction or producing lightning that ignites new blazes.
Plume Collapse and Its Effects
When they run out of energy, they can also trigger what's known as a "plume collapse".
"When the plume collapses, it's a showering of debris, burning debris," said Bowman.
What Does This Mean for Europe?
First Recorded Fire-Cloud in France
French authorities said on Saturday that a pyrocumulonimbus had been observed near Bordeaux, the first recorded in France.
Challenges for Emergency Services
The phenomenon presents an added challenge for emergency services because the erratic nature of fire outbreaks can force authorities to widen evacuation zones as a precaution, said Marc Vermeulen, head of the Gironde fire and rescue service.
Future Outlook for Western Europe
Bowman said Western Europe could now expect to see more of this phenomenon, which tends to occur in more extensive wilderness areas, such as in Canada or Australia.
"This is a very gravely serious milestone," Bowman said. "It is fascinating, but it is also absolutely disastrous and terrible, and we just don't want more of these things."
(Reporting by Coralie Lamarque, Editing by Gabriel Stargardter and Ros Russell)
