Attention: Much of the content on this page is sourced from the National Wildfire Coordinating Group’s Fire Danger Subcommittee and their curriculum for the Geographic Area Rollout Workshops presented in 2018-2020 to transition to the use of NFDRSv4. At the time, NFDRSv4 was referred to as NFDRS2016. Some content will also refer to the Weather Information Management System (WIMS), which has been replaced by FEMS. The explanations in this content for the science behind and the mechanisms within the NFDRS are current and dependable, despite these possible distractions. Work is on-going to update this content with current names and terms.
Overview
This collection of media presents the evolution of the National Fire Danger Rating System from its origins to the present.
NFDRS Background, a brief summary of the evolution of the National Fire Danger Rating System.
NFDRS: Overview, History, & New Science
- Lesson 4 Part 1, slides, lesson plan
- NFDRS - A National System, video (2:42)
- NFDRS - New Science and Technology, video (9:25)
Modernizing the US National Fire Danger Rating System (v4), WM Jolly, et al, 2024
- Publication explaining recent modifications to the National Fire Danger Rating System, including simplified fuel models and improved live and dead fuel moisture calculations, and the benefits of these advancements.
Gaining an Understanding of NFDRS, NWCG, PMS 932, 2002
- Publication providing basic description of the National Fire Danger Rating System
Weather
Hourly weather and solar radiation data, in FW21 format, is required to support NFDRSv4 fire danger analysis in FEMS (and FireFamilyPlus). The FW21 file format provides the data fields required to employ the latest fire danger science, including solar radiation and snow cover, and has the temporal resolution required to support the Nelson dead fuel moisture calculations.
In FEMS, historical, current, and forecast FW21 weather data are available for all Remote Automated Weather Stations (RAWS), regardless of station ownership. Current and forecast data are also available for Automated Surface Observing Systems (ASOS). Other weather monitoring platforms (Mesonet, state-specific databases, etc.) may be added to FEMS in the future.
RAWS QC and Gap-filled Description
NFDRS Model
This collection of media presents the NFDRS Model, and its component fuel models in more detail.
Diagram of the Structure of the NFDRS Model
Dead Fuel Moisture Model
The ‘Nelson model’ for Dead Fuel Moisture is a physical-based model that contains equations for heat and moisture transfer (Nelson 2000). Besides internal water, it also takes into account water at the surface through the processes of adsorption, desorption, rainfall, condensation, and evaporation. Inputs to the Nelson model include air temperature, relative humidity, solar radiation, and amount of rainfall since the last observation. Outputs include moisture content and temperature of the fuel stick at the times corresponding to the weather data inputs. The theoretical model was converted into a finite-difference numerical model, so as to be usable in practice.
Prediction of Diurnal Change in 10-hr fuel stick moisture content, Nelson, 2000. The publication establishing the 'Nelson Model.'
- Lesson 4 Part 2 slides, lesson plan
- NFDRS Fuel Models, video (47:44)
- NFDRS Dead Fuel Moisture Model, video (18:25)
Live Fuel Moisture Model
Growing Season Index (GSI)
- Lesson 4 Part 3 lesson plan
- NFDRS GSI, video (22:44)
A generalized, bioclimatic index to predict foliar phenology in response to climate, M Jolly et al, 2005. The publication establishing the GSI.
Fuel Model Parameters
- See this Table
Fire Danger Rating Areas
Fire Danger Rating Areas are where the rubber meets the road for fire danger rating. They are the spatial summation of analysis to determine where to characterize uniform fire danger for decision making purposes.
Essentials of Fire Danger Rating Areas (FDRAs)
- Lesson 7, slides, lesson plan
Selecting Weather Stations for FDRAs
- Lesson 10, slides, lesson plan
Fire Occurrence
Fire occurrence data are required to conduct NFDRSv4 fire business analyses using FEMS or FireFamilyPlus. Fire occurrence is compared against calculated same-day fire danger values to find statistical relationships between fire activity and fire danger. This allows NFDRSv4 fire danger metrics to be used to help predict fire activity and related fire management business.
Framing the Fire Occurrence
- Lesson 9, slides, lesson plan
- Task 3 Framing the Fire Occurrence
- Planning Area Fire Workload Analysis Chart
- Fire Danger Operating Plan Template
FireFamilyPlus Analysis
Applied Statistics for FireFamilyPlus
- Lesson 12, slides, lesson plan
- Task 5, Matching NFDRS Outputs to Fire Business
- 5a Tech Tip, Reading FFP Graphs
- 5b Tech Tip, FIRES Analysis
- 5c Tech Tip, Goodness to Fit Reference
Defining Breakpoints and Thresholds
- Lesson 14 slides, lesson plan
- Task 6, Analysis for Management Tools and Decisions
- 6a Tech Tip, Fire Business Thresholds
- 6b Tech Tip, Fire Business Thresholds Reference
FireFamilyPlus Data
- FEMS_Default_Blank_V3.mdb
- This is a blank FireFamilyPlus database that has updated station catalog and NFDRS parameters. Some stations may not have historical data (e.g., stations installed after 1/1/2020, but current data are available for download.
- Use of FEMS default FireFamily Plus Database
- To facilitate consistent fire danger rating outputs between FireFamilyPlus and FEMS.
- NFDRS National Settings for FireFamily Plus Catalogs
- National Settings for FireFamilyPlus Catalogs for each RAWS in FEMS 3.0 weather dataset.
Download FireFamilyPlus software
User Support
Full NFDRSv4 Rollout Workshop Curriculum