Incidence of bushfires
The likelihood of a fire occurring, and its severity is heavily dependent on the following:
- the time of the year and weather conditions
- quantity of fuel
- the size, type and dryness of that fuel (dry litter on the forest floor and fine branches less than 8 mm in diameter produce the quickest moving fires)
- winds (the stronger, hotter and drier the wind, the more likely a fire will become rapidly hazardous)
- the dryness of the atmosphere.
In Australia, the vast majority of bushfires are lit by people, whether intentionally or unintentionally. A percentage is started by lightning.
In most of Australia, bushfire season extends from early summer to late autumn, and is concentrated on days with high temperatures and hot, strong, generally northerly winds, usually from the centre of the continent. In northern tropical areas bushfires are more common towards the end of the dry season, predominantly started by lightning.