Forest fires are a devastating natural event. They can happen anywhere that there is enough heat and fuel to burn and can be started by a variety of things. Sometimes a forest fire can be started as simply as a lit match thrown into the dry brush or a lightning strike on ground that is particularly dry. Some fire seasons are more intense than others, depending on the local rainfall but all of them can have huge effects on the local weather both during the fire, immediately after the fire and potentially long term.
One of the most immediate effects that a forest fire can have on weather patterns is the smoke that the fire emits into the atmosphere. This smoke rises into the air up to 6 miles where most of the pollution and particulate matter in the atmosphere resides. However, a large forest fire can also create a thunderstorm. This is called a pyrocumulonimbus storm, notice the use of the prefix pyro which means it was caused by the fire. The formation of this storm pushes the smoke and particulates from the smoke higher into the atmosphere where it will have a more lingering effect. It was once believed that particulate matter that high in the atmosphere was the result of volcano eruptions, but recently the scientific community has started to wonder if these pyrocumulonimbus storm clouds are responsible. Volcano eruptions also create these types of storms but it was believed that only the violent and energetic eruptions could penetrate so far into the atmosphere. It appears now that this belief may have been mistaken.
Another consequence of a forest fire is the destruction of the trees and plant life. These plants and trees are vital to maintaining balance in the environment but also to the weather. Plants are essential for life on this planet as they absorb carbon dioxide from the air and convert it into osygen. Without plant life to perform this function the oxygen levels on earth would severely plummet. Along the same line as the destruction of the plants is that the smoke from the fire spews huge amounts of new carbon dioxide into the surrounding air. This creates a dual problem. One, there is more carbon dioxide in the air than there should have been. Two, there is less plant life to help take that carbon dioxide out of the air. This can have lingering effects on carbon dioxide levels in the areas of a fire for a significant period of time.
All of this smoke and particulate matter in the air means that the air quality in the local region will suffer greatly. Those with asthma or breathing problems may become ill and have a harder time with their illness. Warnings regarding air quality are common during a forest fire and the impact can last for several days or longer. Another immediate impact on the local weather is with heat and wind. These things are effected by the fire and the storm that is created and can cause the local weather patterns to shift slightly until the fire is extinguished.
All of these effects is causing concern that this may negatively impact global climate change. Most of the estimates on climate change use the amount of carbon dioxide and other harmful chemicals are found in the Earth's atmosphere. Fire smoke contains many of these harmful chemicals and emit them into the atmosphere in enormous volume. This means that it is placing a burden on the Earth's climate in addition to other burdening factors. Currently it is not known what this means exactly for climate change in the future, but it is expected that fire prone areas will start to have drier and longer fire seasons as the environment struggles to catch up to the damage.