These components have led to the development of the deadly trio of Fuel, Oxygen and Heat. Remove any one of these and fire will not be able to sustain itself. HEAT. Air temperatures have a direct influence on fire behavior and has all the requirements for ignition and continuing the combustion process. Heat from the sun is transferred to the earth by radiation. This heat warms up the surface of the earth and the atmosphere close to the surface is in turn warmed by heat reflecting from the surface.
Wind also has a strong effect on the heat of a fire because it works like the bellows in a forge, blowing more oxygen into the fire, just like in the old days when people would use an old newspaper as a fan to get the kindling in the wood stove going to boil the kettle and cook meals.
This is the reason that the temperature above the surface is cooler than at the surface of the earth. These temperatures generally decrease about 3.5 C degrees per thousand feet in altitude. This decrease is known as the adiabatic lapse rate. This is why climate scientists are divided on whether to continue with the unreliable method of modelling to estimate temperature or to use the wider coverage and reliability of satellites and factor in the cooling bias.
Forest fuels receive heat by radiation from the sun. As a result, less heat is required for ignition. The differential heating of the earth’s surface is the driving force behind most of the influences on the atmosphere. The sun emits short-wave energy rays (radiation). When striking a solid object such as trees or grass, it is warmed. The surface absorbs some of the heat and reflects some in long-wave radiation that is absorbed by the water vapor in the air thus raising its temperature as well.
At least fifteen percent of fires are lit by natural cause such as lightning and a further thirty five percent are accidental/careless.
WIND supplies extra OXYGEN which also assists combustion. Reduces fuel moisture and increases evaporation. Exerts pressure to move the fire, and the heat produced closer to fuel in the path of the fire increases radiation and blows embers ahead of the fire.
The stronger the wind blows the more it increases the supply of oxygen which results in the fire burning hotter and more rapidly and in the process prepares damp hazardous forest floor material for easy ignition by drying it out.
There are other problems with the wind, it can change speed and direction or become gusty. Wind can also influence the speed and intensity of a bush fire. High winds can cause the fire to crown into the top of the trees and jump fire breaks that would normally stop a fire. Wind can carry sparks ahead of the main blaze creating spot fires ahead of the blaze.
FUEL to BURN. The Australian bush, though it has a reputation for being dry and scrubby, varies greatly from place to place around the country. There are regions of open woodlands, grassland savannas, dense rain forest. A bush fire will burn anything that it finds in its path, but different types of vegetation burn differently. Generally, fuel is classified as being fine (grasses and twigs that are less than 6 millimetres in diameter) or heavy (branches, logs or stumps). Finer fuels burn more easily, feeding the spread of the fire, but heavier fuels burn with greater intensity, creating more heat and making the fire more difficult to put out.