Dew Point as a Basis for the Operational Indicator of Forest Fire Danger

The problem of preventing forest fires and timely mobilization of extinguishing agents is particularly acute in the Irkutsk Region, where forests cover considerable areas. The use of classical indices for assessing forest fire danger does not always provide accurate results in the operational planning of fire extinguishing measures. The aim of this study is to develop a simple and effective indicator for predicting the occurrence of forest fires. The forestries of the Irkutsk Region, which were most severely affected by forest fires, were chosen as the object of this study. In the course of the study, it has been necessary to solve a number of problems, such as assessing the adequacy of the existing methods, developing a more accurate and simple indicator for local conditions, establishing the algorithm for calculating and the scale for assessing the fire danger class. As the initial data, the publicly available data from the meteorological observations archives and the data from the Remote Monitoring Information System of the Federal Forestry Agency (ISDM-Rosleskhoz) have been used. The methods of cluster analysis and correlation and regression analysis have been applied. The dependence of the number of forest fires on weather conditions in sparsely populated areas has been revealed. The frequency of the cycles of the number and area of forest fires is 3–4 years. Various options for calculating the accumulated dewpoint deficit for predicting the number and area of forest fires have been considered. The closest correlation has been found for the indicator calculated over 10 days. Foreign experience in assessing fire danger according to weather conditions having been analyzed, an assumption has been made about the potential partial use of the Australian FFDI index. In the calculations, a satisfactory result has not been achieved. Therefore, it has been proposed to use the accumulated dew-point deficit over 10 days as an indicator of forest fire danger. The number of forest fires is described through the quadratic dependence on this indicator. A scale for assessing fire danger, adapted to the scale based on the Nesterov index, has been developed. For practical use, the calculation algorithm in MS Office Excel has been described, which makes it possible to apply the proposed indicator in the forestries of the Irkutsk Region. The indicator based on the accumulated dew-point deficit over 10 days will make it possible to check the state of forest fire danger according to weather conditions in accordance with the developed scale using the described algorithm and the macro for calculation in MS Excel.