Fire Fighting-Are You Ready

Fire Fighting: Are You Ready?

The Cause of Bushfires:

Relative humidity, high winds and shortage of rain all contribute to increased fire danger in summer. Sunshine and high temperatures rapidly dry timber and grass (source of fuel for fire) which burn very quickly. Hot air lowers the moisture content in forests and grasslands to around 5 per cent and in extreme cases to 2-3 per cent, can greatly increase the speed of the fire.

Humidity: 
Relative humidity is mostly used to measure atmospheric moisture. It is defined as - the ratio of the amount of water vapour actually measured to that which air could hold at saturation. Very low relative humidity, less than 20 per cent, causes the fuel to dry out, therefore becoming more flammable.

Wind: 
Air movement provides oxygen to the fire which it needs to keep burning. Higher winds means more oxygen and more intense flames. Double the wind speed will help to quadruple the rate of the spread of the fire. However above 50 km/h this relationship begins to break down, and above 80 km/h the rate of spread in grasslands reduces. This occurs because the head fire breaks up into narrow tongues, many of which become self-extinguishing. Winds also carry burning embers downwind, which can start new fires. Also known as spotting.

Rainfall: 
Dry grass, dry native shrubs and dead leaves and twigs are a fire's basic fuel. During droughts, in very hot, windy weather, heavy fuels like large logs, green leaves and smaller branches of large trees can become dry and flammable.”

The hot seasonal summer is approaching us fast, and it is now time for us to get ready for the severe fires that have been predicted. To prevent the fires affecting ourselves and our loved ones we need to act to be prepared for when the fires hit!