5 unusual causes of wildfires that will surprise you

People often start wildfires through dangerous actions: pushing a burning car into a gully, mowing the lawn on a hot day or driving with flat tires. This list reveals some of the strangest ways wildfires have ignited.

A vast majority of wildfires are started by people. Human-caused wildfires account for 88% of all wildfires in the United States on average over the last 10 years, according to the National Interagency Fire Center. Human-caused fires are also responsible for 97% of wildfires that threaten homes.

People often start wildfires through dangerous actions, including open burning, campfires, firearms and equipment use. In hot, dry conditions, these actions can quickly escalate into deadly blazes. In California, humans are responsible for about 95% of the state's wildfires, according to CalMatters.org. People often fail to use appropriate judgment, leading to preventable fires, Cal Fire Battalion Chief David Acuna noted.

“Humans are incredibly predictable,” Cal Fire Battalion Chief David Acuna told CalMatters.org. “They drag chains, and they leave campfires to burn, or they have a flat tire but think they can juuust make it to the next exit."

The list below reveals some of the top-five strangest causes of wildfires, including a few that may surprise you.

Lawnmowers

Mowers can create fires by throwing a spark from the exhaust. A person using a lawnmower in Mariposa County caused the French Fire in California on July 4. If you need to mow your lawn, do it before temperatures peak. If it’s windy and dry, the metal blades underneath your mower can easily spark a fire if they strike a rock and experts advise waiting another day.

Animals

Small birds and mammals do not mix well with industrial electrical equipment. Often, the results are catastrophic to humans as well as to the furry or feathered creatures. Rodents often chew on electrical cords and cause fires of all types. Similarly, birds sitting on electrical wires will spread their wings in takeoff and briefly create a connection between conductors. Their electrocuted corpses can ignite a wildfire when they fall to the ground.

Gender reveal party

In one of the more extreme examples of thoughtless human behavior, a smoke bomb used at a gender reveal party in San Bernardino County in 2020 sparked the deadly El Dorado fire, which destroyed five homes and killed one firefighter.

In 2018, a United States Border Patrol agent from Arizona fired a rifle at a target filled with colorful, explosive powder which was intended to reveal the sex of his future child. The target erupted and sparked a fire that was fueled by strong winds and dry grass, eventually consuming 45,000 acres of land. The Saw Mill Fire caused more than $8 million in damages near Tucson.

Compost/spontaneous combustion

Spontaneous combustion of grass or manure piles causes numerous fires each year. Moisture in wet hay piles fosters microorganism growth, which generates heat as they decompose the organic material. This process triggers chemical reactions that accumulate heat, and because hay is a good insulator, the heat is not easily released. When the internal temperature of the hay exceeds 130 degrees Fahrenheit (55 degrees Celsius), it produces flammable gases that can ignite.

Tow chains and flat tires

A tow chain from a trailer can cause a fire by dragging down the road and creating sparks. Authorities say the Flora Fire near Geyserville in Sonoma County was started by a man driving his truck for more than 4 miles without a front tire. The metal scraping on the road sparked the flames.

A similar vehicle-related scenario ignited the 2018 Carr Fire near Redding. The fire, which was one of the most destructive in California's history, killed three people fighting the fire and five civilians and burned nearly 230,000 acres. It was ignited by a spark caused by a couple driving their trailer with a flat tire. The sparks ignited nearby brush and the fire exploded.

Due to a warming climate and other contributing factors, fires are becoming increasingly severe. However, if you live in an area prone to drought or forest fires, you can help prevent natural disasters by following basic fire safety guidelines. All human-caused fires are preventable if care and attention are taken to prevent that ignition spark.