WFDSS & NFDRS Energy Release Component
WFDSS users, including Analysts, Fire Managers & Planners, and Agency Administrators should be aware that the current version of the WFDSS Application is not updating the National Fire Danger Rating System (NFDRS) code to Version 4 (known also as NFDRS 2016) for fire season 2023 and 2024. As a result, WFDSS will continue to produce and use ERC G for use in the Fire Spread Probability (FSPro) model and Fire Danger Graphs.
What this Means for You
- WFDSS uses historical weather observations from the Weather Information Management System (WIMS) and forecast data from the National Weather Service (NWS) to calculate ERC G values and produce fire danger graphs within the WFDSS system itself; WFDSS does not read the ERC values from WIMS.
- The FSPro model in WFDSS is a stochastic model that produces ensemble fire simulations allowing for variability based on historical conditions. It is generally recommended to use 20 or more years of historical ERC values in the FSPro model to account for the range of historic viability. The Fire Environment Mapping System (FEMS) is working to support this need with NFDRS V4.
- The FSPro model uses ERC values to determine burning conditions on a percentile basis. Therefore, the use of ERC G for this purpose is still suitable. Analysts should not attempt to compare absolute ERC G values to Y values. The percentile values and trends should be the same/similar between ERC G from WFDSS and the Y model from WIMS/FireFamily even though absolute values will not be the same/similar. Analysts should continue to use FSPro as they always have; reviewing the ERC G values calculated in FSPro and adjusting the values and percentile bin break points when current and expected fire behavior conditions warrant and as they have been trained.
- As their agency directs and based on NWCG guidance and recommendations, Fire Managers and Planners should transition to the NFDRS Version 4 methodology for their agencies and units. The latest guidance/direction and rollout plan for NFDRS Version 4 is available on the NWCG Fire Danger Subcommittee webpage.