Why Fire Clouds Are Making Europe’s Wildfires More Dangerous

Filippi explains that the storms created by the pyrocumulonimbus, which loom over the fire, create gusts of wind, which in turn lead the water vapor further into the clouds.

“Then the fire is raging more and propagating at [a] higher speed with more energy, so it injects even more water vapor. The cloud is getting bigger, and then it is sucking air [in a stronger way]. Then you have this feedback loop, making an acceleration,” Filippi says.

Those conditions make fires more difficult to contain because the feedback loop continually strengthens both the fire and the cloud above it.

Additionally, studies have found wildfire smoke can make some clouds denser, making it harder for them to drop rain that could help dampen the fires.

Even when water droplets do fall, if the rain is falling into hot air, “it’s gonna evaporate before it reaches the ground,” Filippi says.

Instead, “you’re gonna have a big downdraft. You’re gonna have thunder. Then you can have some other effects, like lifting ashes up into the stratosphere,” he notes, adding that the ash could later fall onto neighboring areas, raising the need for precautionary evacuation measures.