FARSITE

The FARSITE (Forest Area Simulator), which predicts fire spread in two dimensions, is widely used by many land management agencies to simulate the spread of wildfires or fires used for resource benefits (Finney 1996). It is designed for use by those familiar with fuels, weather, topography, wildfire situations and the associated terminology. Because of its complexity, proper fire behavior training and experience are a requisite for using FARSITE for actual fire and land management decisions. FARSITE requires GIS data that is incorporated in the model creation. FARSITE utilizes standard fuel models (Anderson 1982) or the user can define custom fuels.

For those with appropriate background knowledge FARSITE is uncomplicated and easy to operate, with pull-down menus and real-time on-screen graphics. Required input parameters include descriptions of the topography, fuel conditions and amounts (including tree canopy and surface fuels), and weather. Topography and fuels are defined using geographical information system (GIS) data. Wind, humidity and temperature are defined using data streams. Required spatial fuels descriptions include percent canopy cover and distribution of surface fuels. Tree canopy height, height to base of crown, and crown bulk density may be spatial or constants (Finney 1998). Elevation, slope, and aspect inputs must be spatially defined and are typically derived from a digital elevation model (Finney 1998). Fire perimeters and areas resulting from FARSITE simulated fires at each, or user selected time steps, are output as GIS polygon layers. Available raster outputs include time of arrival, fireline intensity, flame length, rate of spread, heat per unit area, direction of spread, and an indicator of fire type (surface, passive crown, or active crown). Output also includes GIS vector files of the predicted fire perimeter at specified time-steps.

Current FARSITE research involves the incorporation of post-frontal combustion simulations to create a more accurate depiction of the smoldering phase and combustion elements present after the initial flame front passes. This post-frontal phase is generally considered to have an effect on fire generated weather patterns including convection columns and widespread heat generation (Finney et al. 2003). Potential research involves the incorporation of mapping suitable safety zones after the initial flame front passes.

The related FlamMap is a fire behavior mapping and analysis program that computes potential fire behavior characteristics (rate of spread, flame length, etc.) over an entire FARSITE landscape for constant weather and fuel moisture conditions.