Thick smoke from and once again in 2026. The are becoming well known, but wildfires’ influence on the weather is less widely recognized.

We often think about weather controlling wildfires: determine when fires start and how quickly they spread. However, once a wildfire becomes intense enough, the relationship can flip. Instead of simply responding to the weather, the fire begins to create its own weather.

I at the University of Texas at Arlington. Here are four key ways wildfires influence the weather around them:

1. Updrafts and fire tornadoes

Wildfires release a large amount of heat. As the air above the flames heats up rapidly, it . As a result, the warm air rises.

This upward motion creates a . In some cases, the rising air becomes so strong that it begins to spin, , also known as a fire tornado.

Forestry officials captured this image of a fire whirl during the Douglas Complex fires in 2013 at Rabbit Mountain, Ore. ,

The process is very similar to how a typical tornado forms, though fire tornadoes tend to be smaller and, because they feed off the heat, confined to the fire area.

2. Fire clouds and thunderstorms

The rising plume of smoke and hot gases also contains and the surrounding atmosphere. As the plume rises, the and , forming a cloud directly above the fire.

Scientists call these clouds pyrocumulus, or .

A pyrocumulus cloud rises above a wildfire in the Angeles National Forest in Southern California in 2012. ,

As water vapor condenses, , making the rising air even more buoyant. If the fire is intense enough and the atmosphere is unstable, the cloud can continue expanding upward into the upper troposphere. It may eventually – a thunderstorm generated by the fire itself.

3. Fire-generated lightning

As the pyrocumulus cloud rises above the point in the atmosphere where the air temperature drops below freezing, cloud droplets begin to freeze, producing ice crystals, supercooled water dropletsand – a soft version of hail.

Collisions among these particles separate positive and negative electric charges within the cloud. Over time, the charge imbalance becomes strong enough to .

Some of these lightning strikes can ignite new fires beyond the original fire perimeter, making firefighters’ jobs even harder.

Lightning is a frequent cause of wildfires. Wildfire smoke can fuel storm clouds that generate more lightning, which can start new fires.

In late July 2026, became intense enough to generate a pyrocumulonimbus cloud. Lightning from the storm ignited new fires outside the original burn area, allowing the fire to spread beyond its initial blaze.

4. Smoke can change weather downwind

Wildfire smoke can also affect weather far from the flames. Smoke can . Along the way, it can influence how clouds form and how lightning develops.

Smoke contains large numbers of tiny particles. These particles act as . Scientists call these seeds cloud condensation nuclei. When wildfire smoke arrives over a region, it increases the number of cloud condensation nuclei in the atmosphere. As a result, the same amount of water is divided among many more cloud droplets, making each droplet smaller.

Smaller droplets take longer to merge into raindrops, which can . This is one reason why forecasting precipitation becomes more challenging during major wildfire events.

A pyrocumulus cloud builds over the Gold Mountain Fire on July 26, 2026, in western Colorado. Sláinte Farms.

Scientists have also found that wildfire smoke can in downwind thunderstorms.

Under normal conditions, about 90% of cloud-to-ground lightning carries a negative charge, while . However, studies have reported unusually .

Positive lightning is than negative lightning. It carries larger electrical currents, lasts longer and releases more energy. As a result, it is more likely to ignite new wildfires and can pose greater risks to people and infrastructure.

, positive flashes accounted for more than 40% of all cloud-to-ground lightning. In the most extreme cases, the fraction exceeded 90%, meaning that nearly all cloud-to-ground lightning was positively charged.

Living with fire and its consequences

The next time wildfire smoke turns the sky hazy, remember that the smoke is not simply drifting through the atmosphere – it is becoming part of the atmosphere.

Wildfires and their smoke can shape clouds, rainfall and lightning in ways we are only beginning to understand. As , living with them will require more than fighting fires. We must also learn to anticipate and adapt to their far-reaching effects on air quality, health and even the weather.

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