What Causes Wildfires?

Understanding what causes wildfires is the first step in protecting your property and contributing to a fire-resilient community. Wildfire causes are complex: some are natural, like lightning strikes, and some are human-caused.

In 2024, 64,897 wildfires burned through 8,924,884 acres, which is well above the decade average. 2025 is on track to continue setting records. As of mid-August 2025, 44,130 wildfires scorched 3,766,597 acres.

How do wildfires start, and how can they leave such destruction? Unfortunately, 89% of the 2024 wildfires were human-caused. Investigations into the causes of the 2025 wildfires, including the LA fires, are ongoing. Eyewitness reports on the 2025 LA wildfires point to faulty power lines, and lawsuits against Southern California Edison, the utility responsible, are already being filed.

How do wildfires start?

Wildland fires start from a combination of three elements: heat, fuel, and oxygen.

• Heat: Many potential heat sources can create embers and ignite wildfires, including human-caused ones.
• Fuel: An arid climate or area experiencing drought creates abundant, bone-dry vegetation that provides copious amounts of fuel for wildfires.
• Oxygen: High winds bring fresh oxygen to embers, fanning flames and making a fire burn hotter. The winds also spread embers, igniting more brush and structures. For example, California’s infamous Santa Ana winds, dubbed “Diablo winds,” bring gusts averaging 45-50 mph, with record gusts clocked at over 160 mph.

What is the most common cause of wildfires?

The main causes of wildfires are related to human activity. Research into how brush fires start records that over the last ten years, humans were responsible for 88% of all wildfires in the U.S. This statistic includes:

• Fires set intentionally for lawful purposes that got out of control
• Those set maliciously, such as arson
• Fires that started due to negligence, like poor maintenance of wires and electricity infrastructure

Human causes of wildfires

How do forest fires start? Why do wildfires happen? Below is a closer look at the most common ways people spark devastating infernos.

1. Burning debris and open fires

One of the most common causes of wildfires is escaped embers from burning debris. On a particularly windy day, escaped embers can carry for miles while staying hot enough to start a new fire.

In many parts of the U.S., burning dead vegetation is illegal. However, in some states, such as California, it’s permitted during certain times of the year. Burning dead vegetation may require a burn permit from your state, county, or municipal government. When burning vegetation and other debris, stay mindful and pay close attention to weather conditions. For more information on burning debris legally and safely, visit your state’s forestry department website.

We typically associate campfires with beautiful memories, like roasting s’mores and sharing stories with loved ones. However, despite a campfire’s summertime appeal, it is one of the leading wildfire causes. The Ham Lake Fire, which destroyed 75,000 acres and hundreds of properties, is just one example of the devastation that a single campfire can cause.

When you go camping, always remember to practice proper fire safety. Smokey Bear is an excellent resource for safety rules on building and extinguishing campfires.

2. Electrical power lines

Fallen power lines rank among the top causes of wildfires nationally — 10% of wildfires are caused by fallen power lines.

The devastating Lahaina wildfire on Maui in 2023 was caused by downed power lines. The 2024 Smokehouse Creek Fire, the largest in Texas history, which also spread into Oklahoma, was caused by a utility pole breaking and sending sparking wires into dry grass. The January 2025 Eaton Fire in Los Angeles County was probably caused by a dormant power line knocked down into a flammable brush by high winds.

While there’s no central national database that records why wildfires happen, between 2000 and 2019, 9,200 miles of powerlines were exposed to large-scale wildfires.

You often hear about huge fires in the Western U.S., but the causes of forest fires in other areas are also related to electrical utilities. The Poor Farm wildfire in New Jersey, the Polk County, North Carolina fire, and the Bugaboo Fire near Sweat Farm Road that burned parts of Florida and Georgia were all started by downed power lines.

Utility companies are learning from past wildfires and developing strategies to lower risks. When studying how wildfires start from power lines, several patterns emerge:

• A falling tree or strong wind can knock them down.
• Trees can grow up into power lines and create an electrical arc.
• Winds can blow lines into one another, called a conductor slap, sending hot metal to dry brush on the ground.

Utilities are working to reduce vegetation around power infrastructure, moving distribution lines underground, investing in digital predictive maintenance, and using targeted power shut-offs when wind conditions are risky.

At Frontline Wildfire Defense, we understand that it’s vital for wildfire defense systems to be able to operate even during power outages. That’s why our exterior sprinkler system features a built-in backup battery. Our system can also be activated remotely, working via satellite communications when Wi-Fi and cell service are unavailable.

3. Arson

When someone deliberately sets a fire in wildlands, they commit the crime of arson. These intentional acts can involve incendiary devices, like matches and lighters used directly on dry vegetation, or can involve lighting an accelerant such as gasoline or lighter fluid.

Some arsonists make “hot sets,” which are small fires placed in strategic places to combine and make a large fire faster. Other arsonists target a building, inadvertently setting fire to the landscape and kicking off a wildfire.

Stopping arsonists is not easy. You can start by making your property less attractive to an arsonist by adding more lighting around your home, staying vigilant, and reporting any suspicious behavior. The arsonist who lit fires during the LA conflagrations was caught by a citizen notifying neighbors and police.

4. Fireworks

Fireworks are another common cause of wildfires. In 2023, fireworks sparked over 27,252 outdoor fires across the U.S. The 2025 Palisades Fire in Los Angeles County is suspected of having started from New Year’s firework celebrations.

The 4th of July is particularly prone to firework-caused wildfires. Between people celebrating outside and consuming alcohol, the hot and dry conditions, and easily obtained incendiary devices, there are twice as many wildfires on July 4th as on any other day.

5. Other accidents

Additional causes of wildfires include:

• Discarded cigarettes: An average of 1,700 wildfires start every year due to discarded smoking materials like cigarettes. If a cigarette butt lands in dry vegetation, it can slowly smolder, gathering heat until a fire breaks out.
• Equipment use and malfunctions: When a piece of machinery malfunctions, it can catch fire or send sparks out in every direction. A vehicle’s broken catalytic converter sent hot metal into the brush on the side of the road, starting the 2018 Ferguson Fire in California. Equipment working normally can also cause fires: Railroad maintenance-of-way machines that grind steel tracks have been identified as a wildfire cause.
• Vehicle crashes: If vehicles crash and catch fire in areas of dry brush, wildfires can result. The Borel Fire of 2024 is a recent example, where a fatal car crash on Highway 178 in Kern County, California, set fire to the nearby hillside. It burned 60,000 acres before being brought under control.

What are the natural causes of wildfires?

What are natural causes of wildfires? While humans cause most wildfires today, the causes of forest fires have historically been environmental and geological events.

Fire is a natural part of the ecology of many areas. Historically, burns have occurred regularly for tens of thousands of years before human intervention. With enough fuel and the right weather conditions, a wildfire can start and spread fast. The most common natural causes are:

• Lightning strikes: 40% of U.S. wildfires and 69% of acres burned in wildfires are due to lightning strikes setting vegetation on fire.
• Dry vegetation and intense sunlight: During periods of high heat without rain, forests, grassy areas, and brush dry out. It takes just one spark to start a fire. Even intense sunlight is enough to set vegetation on fire under dry conditions.
• Volcanic eruptions: While rare in the U.S., volcanic eruptions have been known to start wildfires. Hot lava, ash, and burning embers can set fire to the surrounding landscape.

When discussing what causes wildfires, it’s impossible to ignore climate change. Hotter, drier conditions in the last 30 years have elevated fire risks. From 1992–2020, global warming changed the fire season: It now starts a week earlier in some areas, two months earlier in others, and is now a year-round risk in most areas.

Rising temperatures and drought are part of the problem. In some areas, snow melts earlier, fueling the growth of vegetation that turns into a larger source of fuel. Between 1992 and 2020, 33%-82% of areas burned by wildfire and 65% of total fire emissions in the western U.S. were due to climate change, according to a Cornell University study.

With the conditions for wildfires present nearly year-round, practicing proper fire safety and taking steps to protect your property are crucial. By doing your part in following safety guidelines, you can help prevent future wildfires.

Wildfire causes FAQs

Why are there so many wildfires?

Wildfires have always been part of the natural world. They are growing in number now because of the interplay between climate change, causing hotter, drier conditions, and the impact of human activities.If we reduce human causes of wildfires, we could dramatically cut down the number of wildfires we experience. In light of climate change, we need better ways to live in harmony with wildfires. 

Where are wildfires most likely to occur?

Wildfires are more common in dry, hot areas with plenty of fuel, which includes the western and southern U.S. In 2023, the top five wildfire states were:

• California, with 7,364 wildfires
• Texas, with 7,102 wildfires
• North Carolina, with 5,214 wildfires
• Florida, with 2,730 wildfires

As humans encroach on wild areas, they increase fire risks, both by building in vulnerable areas and introducing human-caused fires to these areas. The wildland-urban interface (WUI), where fire risk is especially high, refers to areas where human buildings border undeveloped forests and grasslands.

Learn to coexist with wildfires

Wildfires are a reality across the U.S., increasing in frequency and intensity. It’s important to learn what causes a wildfire and how to live with the risk of them.

While wildland fires are often unpredictable, you can take proactive steps to protect your property. Creating defensible space, incorporating fire-resistant building materials, and installing sprinkler systems are just a few effective ways to safeguard your home and make your neighborhood more fire resilient.