The National Fire Danger Rating System (NFDRS) has offered a consistent interagency decision-support framework since its inception in 1972. The System was first updated in 1978; and again in 1988. Although the original developers intended for periodic improvements to be incorporated as science and technology improved, the System was fundamentally unchanged for 40 years.
In 2013, research scientists from the USDA Forest Service’s Rocky Mountain Research Station (RMRS) proposed updates to the National Wildfire Coordinating Group (NWCG) Fire Danger Subcommittee. In September 2014, the NWCG Executive Board issued Memorandum 14-018, approving a revision to the US National Fire Danger Rating System. Three significant changes were addressed:
- Incorporate the Growing Season Index (GSI) to compute live fuel moisture.
- Incorporate the Nelson Model to compute fine dead fuel moisture.
- Reduce the number of fuel models in the NFDRS.
These three changes enabled full automation of the NFDRS model processor. And, with a commitment to continuously integrate new science into the model and its applications these changes make it possible to pursue operational applications of hourly and gridded fire danger. In February 2022, the NWCG Fire Danger Subcommittee Issued Memorandum #22-001 providing an update of the transition to the 2016 version of NFDRS, to be formally recognized as NFDRSv4.
NFDRSv4 is the next-generation system which aligns with common interagency goals to use the best available science and technology to provide decision-makers with improved efficiencies, increased accuracy, and a much clearer understanding of the associated risks.
Operational use of the National Fire Danger Rating System is supported by the National Wildfire Coordinating Group Fire Danger Subcommittee.