On the definition of an Exceptional fire danger rating over Mediterranean Countries

The Mediterranean countries are largely affected by wildfires, and appropriate monitoring of daily fire danger is crucial to contribute to quick decision-making and mitigate destructive wildfire disturbances. In operational wildfire monitoring, the Canadian Forest Fire Weather Index System (CFFWIS) is one of the most used fire danger indices, particularly over the Mediterranean region, which rates relative danger of wildfire occurrence by combining six components: three fire behavior indices and three fuel moisture codes. Since FWI results from all components, it is evident that the short and long-term variations of meteorological variables will be reflected and the components will have different influences on FWI values. The main purpose of this work is to contribute to the definition of a new class associated with Exceptional fire weather danger, based on a statistical analysis of FWI, FFMC, and ISI indices for different Mediterranean countries, and for the months between June and October of 2010-2023 period and information of Fire Radiative Power, from the Land Surface Analysis Satellite Applications Facility project (LSA-SAF). Results show, on one hand, that the extreme values of FWI (given by the 99th percentile) of the Mediterranean region are higher in Italy and Greece, in contrast with Portugal and Spain. On the other hand, regarding FFMC and ISI values, higher values can be seen in North African regions for FFMC, and in Italy and Greece for ISI. This is clear evidence of the variations in fire activity in the different Mediterranean regions. A new Exceptional class of fire danger is defined based on the extreme classes of FWI, FFMC, and ISI, jointly based on the occurrence of the recent Megafires in the Mediterranean region, such as the fires in Portugal in 2018 and Greece in 2023. The new approach to define the Exceptional class revealed to be an extremely important tool for fire danger assessment and for the definition of planning activities and suppression measures in the present context of climate warming. Acknowledgements: This study is partially supported by the European Unions Horizon 2020 research project FirEUrisk (Grant Agreement no. 101003890) and by the Portuguese Fundao para a Cincia e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC) UIDB/50019/2020- IDL and DHEFEUS - 2022.09185.PTDC.