BC Wildfire PSTA Head Fire Intensity

Provincial Strategic Threat Analysis (PSTA) is designed to consistently assess and map potential wildfire threats to values across the landscape (including communities, infrastructure and natural resources) and to integrate different aspects of wildfire hazard and risk.

The Head Fire Intensity (HFI) data layer was developed using the 90th percentile fire weather index value for an interpolated and elevation-adjusted analysis of weather station values. This value represents the daily FWI value at which 10% of all interpolated observations at that location exceed the value identified. These were calculated by interpolating daily weather records from the network of active and archived BC Wildfire Service and other (e.g. Environment Canada, BC Ministry of Environment Snow Pillow, etc. ) weather stations. The HFI (90th percentile) values were classified using accepted thresholds of fire intensity and fire suppression effort. The HFI classes used in the final threat layer are different from the defined HFI classes derived from the Fire Behavior Prediction System because the values need to be spread across 10 categories. The intensity values in the HFI data layer therefore represent daily peak burning HFI values representative of a small number of days (~ 1-15) in an average year based on the fuels identified in provincial inventory in early 2017. By definition, these represent high to extreme values for any given location. The final classification scheme for the HFI (90th percentile weather) layer was chosen to represent accepted fire intensity thresholds (in kW/m) associated with suppression difficulty, along with some additional classes added to further discriminate between intensity levels at the high end (i.e. crown fires).Water bodies were overlaid on the raster and assigned their own class, -1. A Private Managed Forest Land (PMFL) and Private Land (PL) mask was applied to the data due to fuel typing limitations in these areas. Each of these were given their own class. PMFL is class -2 and PL is class -3.