‘Fire-breathing dragon clouds’: a wildfire-fueled phenomenon explained

Feared pyrocumulonimbus clouds, akin to fire-triggered thunderstorms, are becoming more frequent as blazes rage

Nasa calls them the “fire-breathing dragon of clouds”.

Aerial images of the McKinney fire taken this week captured an increasingly common phenomenon: a nearly 50,000ft plume known as a pyrocumulonimbus.

The fire, which is raging nearly uncontained in California’s Klamath national forest, is just the latest this year to produce the clouds. They are akin to fire-triggered thunderstorms, explained Derek Mallia, a researcher at the University of Utah who recently co-authored a paper showing how smoke plumes are getting taller, and they are of deep concern to firefighters.


Typically, thunderstorms are initiated by large-scale storm systems like a low pressure zone or a cold front. But if a fire is large enough and there is enough moisture in the atmosphere, it can create its own thunderstorm where smoke mixes with the resulting thunderstorm cloud. “Essentially, the fire is creating its own weather,” Mallia said.

Pyrocumulonimbus clouds are feared for several reasons. When they form above fires, the clouds can make the blaze below spread even faster. Sometimes they can also create their own lightning, which can spark more fires. Fire-triggered clouds tend to be drier and produce less rain, Mallia explained. “This can be problematic as pyrocumulonimbus clouds can produce a lot of wind, which can result in unpredictable fire behavior underneath the cloud and even cause new fires from lightning strikes.” That’s what happened in British Columbia during the summer of 2021, when one fire generated 700,000 flashes of lightning, as many as the province typically gets in one year.

cloud is shaped like a flying saucer
A pyrocumulonimbus cloud is generated by the intense Orroral Valley bushfire burning to the south of Canberra, Australia, in 2020. Photograph: Brook Mitchell/Getty Images

They also can cause fires to move in erratic ways, because they create a vacuum between the cloud and the ground. The hotter a wildfire burns, the more rising air it produces, said David Peterson, a meteorologist at the US Naval Research Laboratory, during a virtual press conference in 2021. “These are pushing smoke upward at extreme velocities, such that they’re injecting smoke at altitudes above the cruising altitude of jet aircraft,” said Peterson. “So we’re talking 50, 60,000 feet, potentially.”

Pyrocumulonimbus clouds are becoming more common and are throwing more pollutants into the upper atmosphere. As fires become larger, with more dry fuels, they produce more heat and smoke, Mallia said.

Lightning flashes over Siskiyou county, California, last month. Lightning strikes sparked new wildfires for crews battling the McKinney fire nearby.
Lightning flashes over Siskiyou county, California, last month. Lightning strikes sparked new wildfires for crews battling the McKinney fire nearby. Photograph: Noah Berger/AP

In some cases, the tall plumes and fire convection can boost aerosols into the stratosphere, like a moderate volcanic eruption – pushing particles into the jet stream that can affect air quality at continental scales. That’s what happened when smoke from fires on the west coast was pushed all the way to New York City. Sometimes the clouds can be so thick that they blot out the sun.

In 2019, Nasa researchers flew a plane through a fire cloud to understand the chemistry of smoke to better understand its impact on air quality and climate.

Scientists are still learning about the fire-triggered storms. Mallia and his colleagues hope to develop ways to predict when pyrocumulonimbus clouds will appear, to help fire managers and firefighters.

And they want to know how the clouds could cause more warming in the atmosphere. Smoke lofted into the lower stratosphere could affect the climate, Mallia said. Smoke particles contain a lot of black carbon, which can result in warming when exposed to sunlight at high altitudes.

“It’s possible that if we see more smoke being injected into the stratosphere, this could result in further warming of our atmosphere,” he said. “If we see this more frequently, this could result in longer-term warming effects.”


Katharine Gammon

The GuardianTramp

Related Content

Article image
Oregon wildfire causes miles-high ‘fire clouds’ as flames grow
Pyrocumulus clouds viewable from 100 miles away as Bootleg fire grows beyond size of New York City

Guardian staff and agencies

16, Jul, 2021 @11:54 PM

Article image
Why Yosemite’s Oak fire is burning with such ferocity – explained
The blaze forced more than 3,000 people to evacuate and exploded to 17,000 acres seemingly overnight – what made it so devastating?

Dani Anguiano

25, Jul, 2022 @10:43 PM

Article image
Surging wildfire tears through northern California town and threatens others
Caldor fire explodes in size as Pacific Gas & Electric begins shutting off power to 51,000 customers

Gabrielle Canon

18, Aug, 2021 @2:27 AM

Article image
‘We got lucky’: inside California’s strangely quiet wildfire year
Fewer acres burned this year, but the need for fire mitigation and the dangers posed by the climate crisis have not vanished

Gabrielle Canon

23, Dec, 2022 @7:00 AM

Article image
Wildfire fighters advance against biggest US blaze amid dire warnings
Oregon’s Bootleg fire 84% contained but parched conditions raise risk of new ignitions

Gabrielle Canon and agencies

02, Aug, 2021 @7:27 PM

Article image
‘I still feel it isn’t real’: Gold Rush town residents reckon with wildfire devastation
As flames approached, Kimberly Price fled her beloved California hometown of Greenville. An hour later, most of it was gone

Dani Anguiano

10, Aug, 2021 @9:14 PM

Article image
‘Fire weather’: dangerous days now far more common in US west, study finds
Hot, arid and dry conditions that fuel extreme wildfires have grown more frequent from Pacific coast to Great Plains

Maanvi Singh in San Francisco

25, Aug, 2021 @2:20 PM

Article image
Breathing wildfire smoke during pregnancy raises risk of premature birth, study finds
Stanford University research estimates that smoky California air may have resulted in as many as 7,000 preterm births

Erin McCormick in San Francisco

24, Aug, 2021 @11:28 PM

Article image
‘This is not typical’: Arizona wildfire fighters brace for threat ‘on steroids’
Winds and dryness heighten danger from Tunnel fire as teams battle blazes in American south-west

Gabrielle Canon and agencies

22, Apr, 2022 @5:34 PM

Article image
How a Tahoe refuge saved owls, coyotes and raccoons from wildfire
Wildfires take a devastating toll on local animals. A Lake Tahoe refuge made sure its creatures didn’t suffer the same fate

Gabrielle Canon in South Lake Tahoe

05, Sep, 2021 @10:00 AM