Have you ever wondered what causes wildfires? Read on to find out.
What is a wildfire?
A wildfire is an uncontrolled fire that spreads through vegetation. These fires:
Commonly occur in rural areas
Can burn through forests, grasslands, savannas, etc.
Are not confined to any single type of environment
What vocabulary do I need to know to better understand wildfires?
Great question! Here are 4 words or phrases you should know to better understand wildfires.
Forest Fires - An uncontrolled fire, specifically in a forested area.
Ground Fire - fire that smolders beneath the surface, burning organic material in the soil and lasting for extended periods (sometimes months!)
Crown Fires – a fire that spreads quickly via tree canopies, aka crowns.
Surface Fires - fire that burns surface material on the ground, including undergrowth and debris.
What causes wildfires?
Many factors contribute to wildfires. The weather is a large part of what creates the ideal conditions for a wildfire. California’s climate, for example, is ideal for fires. Low humidity, rare precipitation, and high temperatures are the 3 main meteorological factors contributing to wildfires.
Firefighters have their own 3 factors for sustaining fire; fuel, oxygen, and a heat source. Vegetated areas unfortunately have 2 of the 3, and humans tend to bring the heat source.
A fire can start naturally but the leading cause is humans; nearly 85% of wildfires in the U.S. are started by humans. Cigarettes, unattended campfires, and trash burning are all ways human activity can cause wildfires.
How do wildfires occur naturally?
Lightning is one of two ways wildfires happen naturally. The National Park Service explains lightning and its connection to wildfires best:
“Lightning is described as having two components—leaders and strokes. The leader is the probing feeler sent from the cloud. The return streaks of light are a series of strokes that produce the actual lightning bolt or flash that we see.
There are two types of lightning—cold lightning and hot lightning. Cold lightning is a return stroke with intense electrical current but of relatively short duration. Hot lightning has currents with less voltage, but these occur for a longer period of time. Fires are usually started by unusually long-lasting hot lightning bolts.”
Volcanic activity is the second way wildfires occur naturally, but this cause is under studied and underreported.
How dangerous are wildfires?
This is where it gets complex. Fire is obviously dangerous for humans, but they aren’t always dangerous to the vegetation!
Small, natural fires are normal and can be beneficial. It clears out underbrush in forests which allows for new plant species to move in. And some species need that extreme heat to release their seeds! Another interesting side effect of fires is the potential to clear out invasive or native species that are harming the ecosystem.
However, past foresters (circa early 1900s) thought all fires were bad and a horrible side effect of human activity. This led to all fires being put out, and now the effects are haunting us today. “The suppression of naturally occurring, low-intensity forest fires has actually aided in the ability for high-intensity wildfires to run rampant” says this National Geographic article.
We know better now and are making efforts to correct this. Letting fires burn out on their own is how nature intended this to happen. So, we monitor burns in remote areas and focus on suppressing fires closer to communities.
How do fires affect wildlife?
The effects of wildfires on wildlife might surprise you! Many animals living in fire-prone areas (hot, dry regions) have adapted to survive fires and even thrive in their aftermath. For example, some species benefit from the changes fires bring to their habitats. However, not all animals are equipped to cope—smaller or slower creatures may struggle to escape and face significant risks.
How does climate change encourage wildfires?
As the earth continues to heat up due to climate change, the risk of wildfires increase. Higher temperatures put us at a greater risk for wildfires, not just in areas meant for them. The hotter and dryer it gets, the more fires we can expect, even in areas not used to them.
Sources:
https://education.nationalgeographic.org/resource/wildfires/
https://www.nps.gov/articles/wildfire-causes-and-evaluation.htm
This page was created by Delaney Meller, '26, an interdisciplinary major in visual arts and communications & media.