Explainer-France has seen its first ‘fire-cloud’. What is it?
By Coralie Lamarque
July 28 (Reuters) – France is grappling with an unprecedented fire season that has forced 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 size of the fires that is groundbreaking. They are also behaving in ways not seen before in France, including the formation of the first pyroculonimbus, or “fire cloud,” reported in the country.
Below is a look at this rare phenomenon:
WHAT IS ‘FIRE CLOUD’?
Pyrocumulonimbus is a cloud that forms over a large wildfire when intense heat drives smoke, ash, and water vapor into the atmosphere.
“You can think of it like a chimney, which means there’s a fire at the bottom and the smoke goes up the chimney straight into the stratosphere,” David Bowman, professor of pyrogeography and fire science at the University of Tasmania, told Reuters.
Jean-Christophe Vincendon, wildfire coordinator for the French national meteorological service, said that although meteorologists can identify conditions that facilitate their formation, they cannot predict precisely when and where a fire cloud will develop.
HOW DO THEY MAKE FIRES WORSE?
Fire clouds can make wildfires more dangerous and less predictable by producing strong winds that change fire direction or lightning that ignites new fires.
When their energy is depleted, they can also trigger a condition known as “feather collapse.”
“When the smoke settles, it’s a shower of debris, burning debris,” Bowman said.
WHAT DOES THIS MEAN FOR EUROPE?
A pyrocumulonimbus has been observed near Bordeaux for the first time in France, French officials said on Saturday.
Marc Vermeulen, head of the Gironde fire and rescue service, said this incident presented an additional challenge for emergency services because the erratic nature of fire outbreaks could force authorities to expand evacuation zones as a precaution.
Western Europe can now expect to see more of this phenomenon, which tends to occur in larger wilderness areas such as Canada or Australia, Bowman said.
“This is a very serious turning point,” Bowman said. “It’s fascinating, but it’s also absolutely catastrophic and terrible, and we don’t want any more of that.”
(Reporting by Coralie Lamarque, Editing by Gabriel Stargardter and Ros Russell)
