How do bushfires happen?

The 4 main environmental factors that increase the chances of a bushfire are:

1. Very low humidity (less than 20%)

2. Lack of rainfall causes dry vegetation. A great source of fuel for bushfires

3. WInds bring oxygen that the fire needs to keep burning

4. High temperatures lower the moisture content of plants

The causes of bushfires can be classified as either natural or human influenced, though a vast majority are caused by humans

The table below shows the causes of bushfires:

Natural

Human influenced

- Lightning strikes release sparks that ignite leaves, branches and other flammable materials/objects. Sometimes these objects continue burning and they cause a bushfire

- Campfires that are left unattended or not properly extinguished

- Farmers burn vegetation on their properties to get rid of crop debris, control weeds and remove rubbish but sometimes it gets out of control when they are not administered carefully

- Machinery or equipment (e.g. chainsaws and grinders) can generate heat or sparks that act as a catalyst for bushfires

- Exhaust from vehicles

- Cigarettes that have been disposed of inconsiderately

- Arsonists who intentionally start fires

The following pie charts displays the percentages of different causes of Australian bushfires: