The FWI system or Forest Fire Weather Index is a system that was introduced in 1970 in Canada. Since then, it has been revised numerous times with the present updated version being issues in year 1987. The UK and Australian versions of the implemented FWI systems follow the version launched in year 1987 (Van Wagner, 1987). In Australia, the system has been modified significantly to adjust according to its dependency on the day length to make sure that the equation of the FWI function remains consistent with the latitude and time of the calendar year. This property of the FWI system allows the FWI fire forecast system to get applied all over the world. An hour based variant of the FWI equation has also been introduced.
The FWI system is relying on the various impacts of weather aspects on the forest surface, and fuel moisture conditions which is a crucial element in the common forest fire behavior. The FWI system needs getting calibrated for its categorization thresholds in accordance with the local climate situation. The calibration of the threshold value is then achieved through the evaluation and assessment of the historical data available about the fire weather information and incidents (de Groot, Wardati. and Wang, 2005). This paper, the threshold values of FWI system for issuing warning of fire danger is planned on the basis of grouping threshold of the FFDI system as implemented in the Australia. A statistical method is utilized to compare these two systems and then develop a conversion mechanism for the FWI value conversion in the FFDI system.
The FWI system is primarily used in the UK region as input for the UK Forest Fire Behavior Prediction (FBP) system. The other inputs entered into the FBP system include the fuel type for the forest fire forecast as well as the topography information available to estimate the behavior of the fire. The FWI system provides two primary outputs based on the assessment of input values- the rate by which the fire would spread and the fuel consumption statistics. The secondary inputs in this situation include the rate by which the perimeter of the fire would grow bigger and the distance of the distance between head, flank and the back of the fire.