Fire, climate change and weather

The Bushfire and Natural Hazards CRC has the latest information on climate change and its effect on fire management. Vegetation in and around wetlands, rivers and streams, rainforests and peat swamps is likely to be most adversely impacted if drying leads to increased frequency of bushfires.

In the south-west, the climate has become warmer and drier and is likely to continue to dry, with lower winter rainfall and increased average temperatures resulting in a longer ‘fire season’ and a greater proportion of the landscape that is sufficiently dry to burn.

In parts of the interior and the tropics, it is likely that rainfall will increase so there may be increased plant growth, promoting increased fuel levels. The change in fire regime that will result is difficult to predict but is likely to favour more frequent, large bushfires.

Western Australia spans the largest range of latitude, has the longest coastline and the most extensive area of arid interior of any state in Australia.

As a result, WA experiences distinctly different climates from the north to the south.

• The north is dominated by a tropical monsoonal climate with regular wet and dry seasons each year.
• The arid interior is affected by predictable seasonal winds and extended periods of drought interrupted at irregular intervals by rainfall events such as thunderstorms and degrading tropical cyclones.
• The south has a Mediterranean type climate with dry, hot summers and wet, cool winters.
• A thin strip around the coast is affected by a maritime influence that mediates the extremes of temperature and drought.

These variations in climate and weather patterns influence the vegetation that occurs across the state and its flammability.

Weather is a primary consideration in fire management. Fire behaviour changes as weather changes throughout the day and between the seasons.

• Rainfall, temperature and relative humidity affect the amount of moisture in the fuels that feed bushfires.
• Wind speed affects the amount of oxygen available to a fire and affects the speed with which a fire will move through fuels.

Knowledge and understanding of weather conditions and patterns and their effects on fire behaviour is fundamental to professional fire management. Being competent and confident in the use and interpretation of forecasts is an essential skill for fire managers.

Parks and Wildlife has a close relationship with the Bureau of Meteorology, whose staff provide specialist forecasting services to the department several times each day. Accurate weather forecasts are essential for fire managers to plan the ignition and control of prescribed burns. The weather information also allows us to monitor the fire danger across the state to ensure appropriate levels of firefighting resources are pre-positioned to effectively respond to any bushfires.