PHOENIX RapidFire 4.0 Convection and Ember Dispersal Model

Classify & Cross-ref
Fire Behaviour
TitlePHOENIX RapidFire 4.0 Convection and Ember Dispersal Model
Publication TypeReport
Year of Publication2012
AuthorsChong, D, Tolhurst, KG, Duff, TJ
Date Published12/2012
Abstract PHOENIX RapidFire is unique in the way it models and incorporates the spotting process in bushfires. There are three main components to the spotting process modelled: lofting, transport, and spotfire ignition. The method of modelling these three processes is described. Lofting is related to the convective strength of the fire and the amount of available ember material, transport is related to wind speed and direction, and spotfire ignition is related to the available fine fuel on the ground and its moisture content. An absence of reliable ember transport and spotfire data has necessitated an empirical approach using the Black Saturday fires in Victoria for model development. As a result, there may be some aspects of the spotting process not well captured in PHOENIX, but to date, the results on new fires have been encouraging. The effective rate of spread of bushfires can be a factor of two or three times greater if the spotting process is well developed compared with a fire, burning under generally similar conditions, but without spotting contributing to the effective rate of spread. Being able to effectively model the spotting process has dramatically increased our ability to model bushfires in eucalypt forests. Modelling the conditions associated with the spotting process has also improved our ability to model potential house loss.