What does FARSITE do?

• Automatically computes wildfire growth and behavior for long time periods under heterogeneous conditions of terrain, fuels, and weather.
• Uses existing fire behavior models for surface and crown fires, post-frontal combustion, and fuel moisture.
• It is a deterministic model, meaning that you can relate simulation results directly to your inputs.
• Produces outputs that are compatible with PC and Workstation graphics and GIS software for later analysis and display.
• Can simulate air and ground suppression actions.
• Can be used for fire gaming, asking multiple "what-if" questions and comparing the results.
• Accepts both GRASS and ARC/INFO GIS raster data themes.

What's new in version 4.1?

Version 4.1 of FARSITE supports the expanded set of standard fuel models developed by Scott and Burgan (2005). These new fuel models are also available in BehavePlus v.3, FlamMap v.3, and NEXUS v.2. Plans include incorporating these fuel models in the Fire and Fuels Extension of Forest Vegetation Simulator in the near future.

Need for a New Set of Fuel Models

NOTE: This section is from:

Scott, Joseph H.; Burgan, Robert E. 2005. Standard fire behavior fuel models: a comprehensive set for use with Rothermel's surface fire spread model. Gen. Tech. Rep. RMRS-GTR-153. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station; 72 p. [ PDF ]

The original 13 fire behavior fuel models have worked well for predicting spread rate and intensity of active fires at the peak of fire season. However, they have deficiencies for other purposes, including prescribed fire, wildland fire use, simulating the effects of fuel treatments on potential fire behavior, and simulating transition to crown fire using crown fire initiation models. Changes in the uses of the Rothermel fire spread model and desire for better "resolution" in choosing a fuel model indicate the need for a new set of models to:

• Improve the accuracy of fire behavior predictions outside of the peak fire season, such as encountered in prescribed fire and fire use applications. For example, the original grass models 1 (short grass) and 3 (tall grass) are fully cured. Applying those models to situations in which the grass fuelbed is not fully cured leads to over-prediction.
• Increase the number of fuel models applicable in high-extinction-moisture areas. Only a few of the original 13 fuel models are appropriate for fuelbeds that burn well at relatively high dead fuel moistures.
• Increase the number of fuel models for forest litter and litter with grass or shrub understory. Predicted surface fire behavior drives crown fire models (Van Wagner 1977, Alexander 1988), so increased precision in surface fire intensity prediction will lead to increased precision in crown fire behavior and hazard assessment.
• Increase the ability to simulate fuel treatments by offering more fuel model choices.

Using the Expanded Fuel Models

The expanded set of standard fuel models are used just like the original standard 13 NFFL fuel models, a numeric index is coded in the fuel model theme (which is used to create the Landscape (.LCP) File). A complete description and list of the expanded set can be found in Scott and Burgan (2005).

Since the ASCII grid raster format accepts only numeric attributes you must use the numeric codes (90 - 255), not the alpha-numeric codes (i.e., GS3, TU2, etc.) for the expanded set in fuel model theme. These are listed in the Scott and Burgan paper.

Backward Compatibility

Project (.FPJ) and Bookmark (.BMK) Files created in version 4.0 are fully compatible with version 4.1. Simply open the existing files the same way you did in version 4.0.

Custom Fuel Model File Format

The new Custom Fuel Model (.FMD) File format was designed to be interchangeable between fire behavior applications. For example, custom fuel models created in BehavePlus v.3 can be saved in the .FMD format used in FARSITE v4.1.