Overview

FARSITE automatically computes wildfire growth and behavior for long time periods under heterogeneous conditions of terrain, fuels, and weather. It uses existing fire behavior models for surface fire spread (Rothermel 1972), crown fire initiation (Van Wagner 1977), and crown fire spread (Rothermel 1991), post-frontal combustion (Albini and others 1995; Albini and Reinhardt 1995), and dead fuel moisture (Nelson 2000).

FARSITE is a deterministic modeling system, meaning that simulation results can be directly compared to inputs. This system can be used to simulate air and ground suppression actions as well as for fire "gaming," asking multiple "what-if" questions and comparing the results.

FARSITE is a spatial fire modeling system that produces outputs that are compatible with PC and Workstation graphics and GIS software for later analysis and display. It accepts both GRASS and ARC/INFO GIS raster data themes.

Where FARSITE Fits In

FARSITE is part of a suite of fire behavior systems that includes BehavePlus, FlamMap, and FSPro. These are complementary systems that are based on essentially the same fire models. BehavePlus is a point system with input supplied interactively by the user. FlamMap, FARSITE, and FSPro are spatial systems that use the same base GIS data. Following are some points of comparison:

• BehavePlus fire modeling system
  • Can be considered a 'point' system.
  • Each calculation is for a set of uniform conditions.
  • Rarely is a single calculation done.
  • The user looks at the effect of a range of values on the results.
  • Input is entered by the user. GIS data are not used.
  • Results are in the form of tables, graphs, and simple diagrams.

• FlamMap fire mapping and analysis system
  • Adds the spatial component.
  • Point calculations are done for each pixel.
  • Conditions are constant in time, but vary in space.
  • Minimum travel time and other options are also available in FlamMap.
  • Used to examine potential fire behavior across the landscape.

• FARSITE fire area simulator
  • Adds the temporal component.
  • Conditions vary in both time and space.
  • Fire growth simulation.
  • The fire behavior at a pixel depends on the adjoining pixels and the time it burned.

• FSPro fire spread probability
  • Probability of fire spread from a known perimeter or point.
  • Not a fire perimeter like FARSITE.
  • Not a projection of fire size.
  • Results are based on thousands of FARSITE simulations for simulated weather sequences.
  • FSPro modeling requires computing power beyond that available on a personal computer.