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  • Ben Jones

How Do Wildfires Start?

Updated: May 14

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how do wildfires start?


Wildfires represent one of the most vivid and destructive forces of nature, affecting our environment, societies, and economies on a global scale. The initiation and spread of these fires have far-reaching implications, making an understanding of their causes not just a matter of scientific interest, but a crucial aspect of public safety. environmental conservation, and forest management.

Previous blogs have looked at recent wildfire trends and have delved into what exactly makes something a wildfire. This article will look more closely at how wildfires start.

By dissecting the complex interplay of natural elements and human actions that lead to wildfires, we aim to foster a deeper understanding of these phenomena, laying the groundwork for more effective management and mitigation strategies.

Through this exploration, we hope to answer critical questions about wildfire causes: How and why do these fires start? What can we learn from them? And how can we better protect our planet and communities from their destructive power?

Impact of Wildfires

The devastation caused by wildfires extends far beyond immediate destruction. These catastrophic events result in the emission of billions of tonnes of carbon dioxide, significantly contributing to global greenhouse gas levels. The ecological impact is profound, with a staggering number of wildlife fatalities estimated in the billions, disrupting delicate ecosystems.

Economically, the toll is immense, with damages and losses running into hundreds of billions of dollars. Moreover, the health consequences of wildfires cannot be overlooked. Smoke and pollutants released during these fires pose serious respiratory risks and can lead to long-term health complications for people in affected areas.

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To learn more about the often overlooked consequences of forest fires and explore effective solutions to mitigate their devastating impact, we invite you to download our whitepaper, 'What Lies Beneath: the hidden truth about wildfire.'

This in-depth paper delves into the far-reaching effects of forest fires, exposing the detrimental consequences on our environment, the loss of precious lives, the profound impact on wildlife, and the staggering economic costs incurred.

Moreover, it sheds light on the latest technological advancements that are playing a pivotal role in combating these fires and safeguarding our communities and natural resources.

Are Wildfires Getting Worse?

The number of wildfires, the amount of land they burn, and the number of people they displace are all increasing. This is due to a number of factors, including climate change, drought, and human activity.

Climate change is intensifying the Earth's climate, leading to higher temperatures and increased dryness. These conditions are prime for the initiation and rapid spread of wildfires. Additionally, droughts, becoming more frequent and severe, exacerbate this issue by drying out vegetation, making it highly susceptible to ignition.

Further in this article, we will delve deeper into how human activities, including arson, irresponsible management of campfires, and sparks from power lines, significantly contribute to the incidence of wildfires.

Where Do Wildfires Occur?

Wildfires can occur in various parts of the world, but they are most commonly associated with regions that have a combination of dry climates, abundant vegetation, and a history of fire activity. Some of the areas where wildfires are most common include:

  • Western United States: States such as California, Oregon, Washington, and parts of Nevada and Arizona are prone to wildland fires due to their dry summers, strong winds, and extensive forests.

  • Australia: The southern and eastern parts of Australia experience severe bushfires, especially during the hot and dry summer months. The country has a long history of devastating bushfires.

  • Mediterranean Europe: Countries like Spain, Portugal, Italy, and Greece have a Mediterranean climate characterized by hot, dry summers, which often lead to significant forest fires.

  • Amazon Rainforest: Portions of the Amazon basin, primarily in Brazil, experience wildfires, often caused by human activities like deforestation and land clearance.

  • Siberia and Russia: Siberia and parts of Russia witness large-scale wildfires, particularly in remote forested regions, during the summer months when the vegetation is dry.

  • Southeast Asia: Countries like Indonesia, Malaysia, and parts of Thailand and Vietnam experience wildfires, often associated with land clearing practices like slash-and-burn agriculture.

It's important to note that wildfires can occur in other regions as well, depending on local conditions, such as drought, high temperatures, and the presence of flammable vegetation. Additionally, climate change can influence fire patterns, making some regions more prone to increased fire activity.

The vast range of countries where Dryad Networks currently has reseller partners deploying Silvanet is testament to the growing number of regions that suffer from the scourge of forest fires.

Natural Causes of Wildfire Ignition

Though overwhelmingly caused by humans, wildland fires can be naturally occurring. These causes can vary depending on a particular region’s climate, vegetation and topography. Natural causes of fires include lightning strikes, volcanic eruptions and fires being ignited by the sun’s heat.

Lightning Strikes

The most common cause among naturally occurring wildfires is lightning strikes. Lightning can hit power cables, trees, shrubs, or dry grass and cause forest fires to ignite.

According to the BBC, more than 12,000 dry-lightning strikes started over 650 wildfires across California in August 2020, burning more than 1.5 million acres of land, with hundreds of thousands of people evacuated.


Volcanic eruptions are another natural cause of forest fires. Hot magma from the earth’s crust is expelled as lava during a volcanic eruption, causing it to flow down mountainsides and spread out over the forest floor, starting fires.

Because the lava from a volcanic eruption has such a high temperature, it burns everything in its path and the fuel does not need to be very flammable.

Spontaneous Combustion

Decomposing organic materials, such as piles of dry leaves or compost, can produce heat over time. If the heat accumulates and reaches a critical point, it can ignite a fire. With increasing incidences of extreme weather events and therefore higher wildfire risk, this phenomenon is set to increase.

natural causes of wildfire ignition

The Role of Human Actions in Sparking Wildfires

As mentioned, people are to blame for the vast majority of wildfire instances around the world. What’s worse is that research suggests that human ignition is to blame for a staggering 97% of wildfires that threaten homes in the US.

Quoted in, Stijn Hantson, a fire ecologist at the University of California, said that human-caused wildfires spread twice as fast as naturally-caused ones, burn more intensely, and kill “double or triple” the amount of trees.

human caused wildfires statistic graphic

What then, is the predominant factor in wildfire outbreaks? The answer frequently lies in human negligence. Careless acts such as arson, unattended campfires, improperly discarded cigarettes, and reckless use of matches or fireworks stand as the foremost reasons behind wildfire ignitions. These fires may arise both from intentional misconduct and inadvertent carelessness.


A grim and sobering fact about forest fires is that many are started intentionally as acts of arson. Arsonists’ motives can be hard to discern, but are said to include real estate speculation, building land reclamation, and pasture management.

According to a report by the National Fire Protection Association, there were 52,260 intentional fires started between 2014 and 2018 in the US. These resulted in an estimated 400 civilian deaths, 950 civilian injuries, and $815 million in direct property damage each year.

Unattended Campfires

Campfires that are left unattended or that aren’t properly and completely extinguished are a common cause of human caused fires.

Left unattended, campfires can quickly get out of hand. They can then turn into wildfires themselves or emit burning embers and ash that spark fires nearby.

Campfires are often enforced by local authorities, who insist that they should only be held in rock-ringed fire pits and not until there are shovels and a plentiful supply of water nearby. However, these rules are often not adhered to and many campfires are started outside of designated campsites and areas, making them harder to control and manage.

Just as important as controlling the fires themselves is ensuring that they are properly put out. Simmering and sizzling embers can stay hot for hours (sometimes days) after a fire has ostensibly been extinguished. These can then be blown elsewhere by strong winds and are often still a hot enough heat source to start new fires. If this happens in hot, dry climates where there's a lot of vegetation, a blazing wildfire can start in no time.

One of the devastating forest fires caused by unattended campfires was the Ham Lake fire in 2007. As well as hundreds of properties, this fire burned down 75,000 acres of forest along the Gunflint Trail in northeast Minnesota.

Burning Debris

In a similar fashion, carelessness when it comes to debris burning can easily lead to a catastrophic uncontrolled fire. With the right weather conditions, people burning yard debris in their yards could easily spell a wildfire in the works. For example, wind can cause the flames rising from a pile of burning yard waste to unwanted areas, starting new fires.

Insufficiently extinguished fires again pose a significant fire risk. Fires can look like they’re completely burnt out, only for a smoldering ember to catch in the wind and start a whole new fire elsewhere.

Equipment, Machinery and Infrastructure

Research shows that broken or faulty power lines are the third most common cause of forest fires and are responsible for 10% of wildfires (approximately 400 fires) per year in California.

We already know that, in the right circumstances, all that’s needed to start a forest fire is a spark.

Equipment malfunctions and sparks from engines are a significant cause of forest fires around the world. For example, farm equipment or machinery used by construction companies are often to blame. While many such machines are now equipped with spark arrestors, these devices aren’t able to completely eradicate sparks, meaning they can still be blown astray and be capable of starting new fires.

For example, Zaca Fire (2007), the fifth biggest California wildfire on record, was caused by sparks from a metal grinder. The Carr Fire (2018) was ignited by sparks from a trailer's broken wheel rim and is the seventh-most destructive fire in California's history.

Discarded Cigarettes

Lit cigarettes are often discarded from buildings and cars and these can ignite the dry vegetation on which they land, starting fires that can quickly spread.

In 2017 in the US alone, forest fires caused by discarded cigarette butts were responsible for $6 billion in property damage.

human causes of wildfires


It's evident that these natural disasters are a multifaceted problem with deep environmental, social, and economic repercussions. The increasing frequency and severity of wildfires, driven by climate change and human activities, underscore the urgent need for concerted efforts in prevention and management.

This article has illuminated the diverse natural phenomena and human actions that ignite wildfires, from lightning strikes and volcanic eruptions to irresponsible campfire management and equipment malfunctions. Our journey through various global hotspots for wildfires reveals a clear message: no region is immune to the threat, and collective action is essential.

The fight against wildfires is not just about combating flames; it's about understanding and respecting the intricate balance of our natural world and the impact of our actions. Education, policy-making, and technological advancements play pivotal roles in this battle. As we move forward, it's crucial to integrate sustainable practices, enhance early detection systems, and foster global collaboration to mitigate the impact of wildfires.

Wildfire Causes at a Glance

How do wildfires start?

Wildfires typically start due to a combination of dry vegetation, hot conditions, and an ignition source. Natural causes include lightning strikes and volcanic eruptions. Human activities, such as campfires left unattended, discarded cigarettes, and arson, are also major contributors. Additionally, factors like climate change and droughts can exacerbate the likelihood and severity of wildfires.

What is the most common cause of wildfires?

The most common cause of wildfires worldwide is human activity, accounting for the majority of wildfire occurrences. Factors such as unattended campfires, discarded cigarettes, equipment malfunctions, arson, and other forms of human negligence contribute significantly to the ignition of wildfires.

How do wildfires start naturally?

Natural causes of wildfires primarily include lightning strikes, which can ignite dry vegetation, and volcanic eruptions, where hot lava sets fire to its surroundings. Additionally, spontaneous combustion can occur in hot conditions, especially in areas with a lot of dry organic material.

How do human activities contribute to starting wildfires?

Human activities that lead to wildfires often involve negligence, such as leaving campfires unattended, improperly discarding cigarettes, and using equipment that sparks. Arson, the deliberate setting of fires, is also a significant human cause of wildfires.

Can climate change affect wildfire frequency and intensity?

Yes, climate change plays a critical role in increasing the frequency and intensity of wildfires. It contributes to longer drought periods, higher temperatures, and drier vegetation, all of which create ideal conditions for wildfires to ignite and spread more rapidly.

How fast do wildfires spread?

The speed at which wildfires spread can vary widely depending on factors such as wind speed, terrain, vegetation type, and weather conditions. On average, wildfires can move at speeds ranging from 6 to 14 miles per hour (10 to 23 kilometers per hour) in forests and grasslands. However, under extreme conditions, wildfires have been known to spread much faster, reaching speeds of up to 60 miles per hour (97 kilometers per hour) or more in certain situations.

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Alexander Svensk
Alexander Svensk
Aug 06, 2023

You failed to mention that spontaneous combustion in organic material happens at around 300 to 500 degrees Celsius or 572 to 932 Fahrenheit, a so called flashover. You can however get spontaneous combustion in compost at 150 to 200 degrees Celsius if there is to much water, which causes it to go anaerobic, producing methane, which then then is combusted.


Horst Schrader
Horst Schrader
Oct 12, 2022

Substantial information , very impressive Spread the facts !

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