Fire Behavior Outputs

Fire behavior outputs are a key component of the model used to estimate the WFSI. Potential fire behavior can be evaluated using a fire behavior prediction program, much like FARSITE (Fire Area Simulator) (Finney 1998) and FlamMap (Finney 2006). For the FRA, the FlamMap program was used.

The fire behavior program uses topographic information, fuel characteristics, and weather to calculate rate-of-spread, flame length, fire type, and other characteristics of fire behavior. Fire behavior prediction can also be done using a fire behavior dynamic link language (dll) program, which provides a more flexible and customizable method of calculating the required fire behavior outputs needed for the risk assessment model. The fb3.dll used in the SFRA has the advantage of providing tight integration capabilities with GIS systems and other programs.

The main fire behavior variable calculated by the fire behavior prediction programs such as the fb3.dll for the calculation of the WFSI is fire spread rate. This variable was developed because it can be used to estimate a fire’s expected size.

For further analysis and display, it is worthy to note that additional fire behavior outputs such as fire intensities and flame length are available outputs of the fb3.dll program. The FlamMap program and the fb3.dll calculate the behavior of a fire occurring in each 30- by 30-m cell under defined weather conditions. Fire behavior is described independently for each individual cell.