Wildfires Can Create Their Own Weather, Further Spreading The Flames
Satellite data shows fire-produced thunderstorms are much more common than anyone realized just a few years ago.
Wildfire , fire whirls, towering thunderstorms: When fires get large and hot enough, they can actually create their own weather.
In these , firefighters’ ordinary methods to directly control the fire don’t work, and wildfires burn out of control. Firefighters have seen many of these risks in the burning near Chico, California, and other wildfires in summer 2024.
But how can a fire create weather?
I’m an who uses data collected by satellites in to better anticipate extreme fire weather phenomena. Satellite data shows fire-produced thunderstorms are much more common than anyone realized just a few years ago. Here’s what’s happening.
The Wildfire And Weather Connections
Imagine a wildland landscape with dry grasses, brush and trees. A spark lands, perhaps from lightning or a tree branch hitting a power line. If the weather is hot, dry and windy, that spark could quickly ignite a wildfire.
When vegetation burns, large amounts of heat are released. This heats the air near the ground, and that air rises like a hot air balloon because hot air is less dense than cool air. Cooler air then rushes in to fill the void left by rising air.
This is how .
What happens next depends on the . If the temperature cools rapidly with elevation above the ground, then the rising air will always be warmer than its surroundings and it will keep rising. If it rises high enough, the moisture will condense, or flammagenitus.
If the air keeps rising, at some point the condensed moisture will freeze.
Once a cloud has both liquid and frozen water particles, can lead to . If the charge buildup is large enough, an electrical discharge – better known as lightning – will occur to neutralize the charges.
Whether a fire-induced cloud will become a thunderstorm depends on : a source of lift, instability and moisture.
Dry Lightning
Wildfire environments typically have limited moisture. When conditions in the lower atmosphere are dry, this can lead to what’s known as .
No one living in a wildfire-prone environment wants to see dry lightning. It occurs when a thunderstorm produces lightning, but the precipitation evaporates before reaching the ground. That means there is no rain to help put out any lightning-sparked fires.
Fire Whirls
As air rises in the atmosphere, it may encounter different wind speeds and directions, a condition known as . This can cause the air to spin. The rising air can tilt the spin to vertical, .
These fire whirls can have powerful winds that can spread flaming ash, sparking new areas of fire. They usually are not true tornadoes, however, because they aren’t associated with rotating thunderstorms. https://www.youtube.com/embed/AIkz4K5yTXI?wmode=transparent&start=0 A time-lapse video shows a large fire whirl during the Park Fire near Chico, Calif., in July 2024.
Decaying Storms
Eventually, the thunderstorm triggered by the wildfire will begin to die, and what went up will come back down. The downdraft from the decaying thunderstorm can produce , further spreading the fire in directions that can be hard to predict.
When fires create their own weather, their behavior can become more unpredictable and erratic, which only amplifies their threat to residents and firefighters battling the blaze. Anticipating changes to fire behavior is important to everyone’s safety.
Satellites Show Fire-Created Weather Isn’t So Rare
Meteorologists recognized the in the late 1990s. But it wasn’t until the launch of the satellites in 2017 that scientists had the necessary to see that fire-induced weather is actually commonplace.
Today, these satellites can alert firefighters to a new blaze . That’s important, because there is an in the number, size and frequency of wildfires across the United States.
Climate Change And Rising Fire Fisks
Heat waves and drought risk have been , with rising global temperatures more frequently leaving dry landscapes and forests primed to burn. And climate model experiments indicate that .
As more people move into fire-risk areas in this warming climate, the is also rising. With fires come that persist long after the fire is out, such as burn-scarred landscapes that are and debris flows that can affect water quality and ecosystems.
Communities can reduce their by building defensible spaces and firebreaks and . Firefighters can also reduce the surrounding fuel loads with prescribed fire.
It’s important to remember that fire is a natural part of the Earth system. As fire scientist writes, we as humans will have to reorient our relationship with fire so we can learn to live with fire.
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