Summary
- Lightning strikes are the number one cause of bushfires
- People also cause bushfires, usually by accident
- Fire needs three things to exist: heat, oxygen and fuel (vegetation)
- Be fire safe when you're outdoors and stop bushfires starting
- Causing a bushfire is a crime, even if it's accidental
Bushfires start due to natural and human causes
Learn more about how fires start and spread in the video below.
[How Bushfires Start]
Some fires start from natural causes we can't control, like lightning.
When fire reaches trees, grass and plants, it spreads fast. The more fuel a fire has, the bigger and more intense it becomes.
But many fires start because of people.
Campfires, machinery and other activities near dry vegetation can quickly spark a bushfire.
A campfire that isn't watched or put out properly can spread to dry grass and trees starting a dangerous bushfire.
If you don't supervise a burnoff or if it's too windy, it can get out of control and cause a bushfire.
Cooking outside with wood, coals or heat beads can start a fire if you are not careful, especially when it's dry or windy.
A dropped cigarette isn't just litter - it can easily ignite dry grass and cause a bushfire.
Hot car exhaust can set dry grass on fire. Driving or parking on long grass, even on the side of the road, is a fire risk.
Using tools like angle grinders near dry grass can create sparks that start a fire within seconds.
You can help prevent bushfires by being fire safe when exploring the outdoors, holidaying in the countryside, using fire in the backyard or working on a farm.
Fires can start anytime, so always be prepared.
If you start it, you own it.
Take responsibility and don't be that person who accidentally starts a bushfire.
Lightning strikes are the most common cause of bushfires
Lightning is the most common cause of bushfires and grassfires in Australia.
More than 90% of the area burned during the Black Summer 2019-20 bushfires can be traced back to fires started by lightning.
Because lightning is common and out of your control, you need to be prepared for bushfires to happen at anytime. Stay across any fires in your area with VicEmergency and make sure you have a fire plan.
Human causes of bushfire
People can also start fires, either accidentally or on purpose.
Bushfires can be caused by:
Fires can also start due to sparks from:
You can prevent bushfires starting by being fire safe when exploring the outdoors, holidaying in the country, or working on the farm.
Fire Science: the fire triangle
Fire needs three things to exist: fuel, heat and oxygen.
Fires need three things to start and continue burning. Fuel, oxygen and heat. Remove any one and the fire can't burn.
Fire is a chemical reaction. Three things are needed for fires to start, burn and keep burning.
1. Fuel (vegetation)
A fire needs something to burn.
In bushfires, this is vegetation—trees, bushes, plants, grass—and other structures or objects like houses or sheds.
2. Heat
A fire can't start or continue to burn without heat. Heat sources that can start a fire include lightning, campfires, car exhaust and cigarettes.
Once a fire starts, the fire itself becomes the heat source that keeps the fire going.
3. Oxygen
A fire can't burn without oxygen. Oxygen is part of the chemical process that creates fire.
Remove fuel, heat or oxygen to put the fire out
If any one of the three ingredients of a fire is removed, it will go out.
1. Fuel is removed
If there isn't enough vegetation for a fire to burn, it will eventually go out.
Firefighters create breaks in vegetation (fire breaks) on purpose to stop fire spreading. Prune and remove vegetation on your property to stop fire reaching your home.
2. Heat is removed
For example, putting water on a fire cools it down and puts it out.
3. Oxygen is removed
For example, firefighters use foam to stop a fire getting more oxygen. Fire blankets are used in kitchen fires for the same reason.
Take care not to start a bushfire
Causing a bushfire is a serious crime. It's a crime even if you didn't mean to start one.
Penalties for recklessly causing a bushfire or grassfire include up to 15 years’ imprisonment.
Reckless behaviour can include:
The maximum penalty for deliberately starting a fire resulting in death is 25 years’ imprisonment.
If you see reckless or intentional behaviour that could lead to a bushfire, report it. Contact Crime Stoppers on 1800 333 000.
Don't be the person that accidently starts a bushfire - know what you can and can't do during the Fire Danger Period and on Total Fire Ban Days.
Resources
Can I or Can't I?
There are fire restrictions during the Fire Danger Period and on Total Fire Ban days. Find out what you can and can't do legally so you can avoid big fines and/or jail time.
Page last updated: Wednesday, 9 September 2026 4:20:17 PM