Large wildfires can do more than destroy forests they can also create their own weather, according to a new research brief published by PreventionWeb. Researchers say intense fires generate powerful heat and smoke that influence wind patterns, cloud formation, rainfall and lightning, sometimes affecting areas hundreds of kilometres away from the flames.
According to Yunyao Li from the University of Texas at Arlington, the relationship between weather and wildfires is two way. While weather conditions such as heat, dry air and wind influence how fires spread, extremely intense wildfires can begin altering the atmosphere around them.
One of the most striking effects is the formation of fire whirls, or fire tornadoes. As the intense heat causes air above the flames to rise rapidly, strong updrafts develop. Under certain conditions, these updrafts begin to rotate, creating spinning columns of fire that can spread flames and make firefighting operations more dangerous.
Wildfires can also produce pyrocumulus clouds, commonly known as fire clouds. As smoke and hot gases rise, the water vapour they carry cools and condenses. If atmospheric conditions remain unstable, these clouds can develop into pyrocumulonimbus clouds thunderstorms generated entirely by the wildfire.
These fire generated thunderstorms can produce lightning, creating another major hazard. Researchers noted that lightning from these storms can ignite new wildfires beyond the original burn area, allowing fires to spread rapidly. During a severe wildfire near Saumos in southwestern France in July 2026, lightning generated by a fire induced thunderstorm reportedly sparked new fires outside the initial blaze.
The study also highlights that wildfire smoke can influence weather far from the fire itself. Smoke particles act as cloud condensation nuclei, causing clouds to form with a larger number of smaller droplets. This process can delay rainfall or shift where precipitation occurs, making weather forecasts more difficult.
Researchers further found that smoke can alter lightning patterns by increasing the occurrence of positive cloud to ground lightning. Unlike the more common negative lightning, positive lightning carries greater electrical energy, lasts longer and is more likely to ignite new fires while posing greater risks to people and infrastructure.
The researchers said wildfire smoke becomes part of the atmosphere, affecting cloud formation, rainfall and lightning over large distances. As large wildfires become more frequent, they stressed that improving forecasting and understanding these weather interactions will be essential for disaster preparedness and reducing future wildfire risks.