NBIC-ACS Stage 2 Canadian Forest Fire Weather Index - baseline scenario, 20% and 10% annual exceedance probabilities

The Canadian Forest Fire Weather Index (FWI) is a fire weather potential index that describes how current weather conditions and recent precipitation patterns could support a landscape fire. FWI calculations are based on Van Wagner & Pickett (1985) and Van Wagner (1987), and dependent on air temperature, relative humidity, wind speed and precipitation. The metric was developed with the worst conditions believed possible in Canada corresponding to a value of 200, although in Australia values above 200 are regularly reported. This metric was also originally developed for boreal forests, although was later generalised to different climate and vegetations. Here we provide predicted upper-bound FWI values across the Australian landscape, defined for a set of Annual Exceedance Probabilities. We calculate FWI based on the latest Bureau of Meteorology historical weather reanalysis BARRA-R2, reporting modelled hourly weather conditions from 1979 to current at a spatial resolution of approximately 11 kilometres. More than 400,000 data points at every location are then processed using the National Bushfire Intelligence Capability (NBIC) Extreme Values Analysis to predict extreme daily maximums and their likelihood. FWI is not used routinely in Australia, however it is the reference fire weather metric for other national and international contexts. As such it can play an important role in reporting the evolution of Australian bushfire hazard in international forums. All these characteristics result in datasets that are a significant advancement in defining extreme fire weather, surpassing previous approaches and offering a robust foundation for informed decision-making in managing and mitigating Australia’s growing bushfire risks in a changing climate.\nLineage: The Canadian Forest Fire Weather Index (FWI) - baseline scenario is calculated using the historical weather reanalysis dataset BARRA-R2 by Bureau of Meteorology (https://dx.doi.org/10.25914/90rq-d839). Variables used are near surface air temperature, near surface relative humidity, precipitation and near surface wind speed.\n\nHourly weather variables are sampled or accumulated to 12PM (used as reference hour of the day), then combined using the equations developed by Van Wagner & Pickett. (1985) [1] and Van Wagner (1987) [2]. FWI is calculated for more than 43 years of daily weather data and then processed using extreme values analysis to model the expected FWI values at annual exceedance probabilities.\n\n[1] Van Wagner, C.E.; Pickett, T.L. 1985. Equations and FORTRAN program for the Canadian Forest Fire Weather Index System. Canadian Forestry Service, Petawawa National Forestry Institute, Chalk River, Ontario. Forestry Technical Report 33. 18 p.\n[2] Van Wagner, C.E. 1987. Development and structure of the Canadian Forest Fire Weather Index System. Canadian Forestry Service, Headquarters, Ottawa. Forestry Technical Report 35. 35 p.\n\n\nImportant Disclaimer:\nCSIRO advises that the information contained in this dataset comprises general statements and information based on scientific research. The user is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, CSIRO (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it.