Fire spread across different fuel types: research and utilisation – final project report

This publication provides an overview of two new models for understanding aspects of bushfire behaviour in Australia. It is crucial for emergency and disaster management organisations to predict the rate of spread and intensity of bushfires for operational planning, community warnings and the deployment of their resources. Currently, this is achieved by simulation using simplified operational models that have the useful attribute of providing results on time scales commensurate with those required by emergency managers.

However, a review of the performance of the operational fire models used by fire and emergency service analysts on seven vegetation types found in Australia, found that on average most of the fire models have an error of 20–80% in estimating the rate of fire spread. These differences in prediction are due to the assumptions and limitations of these models. Therefore, it is essential that these simplified operational tools be refined so that they can better predict fire behaviour. Additionally, a more physically based firebrand model needs to be included in operational models to predict firebrand distribution and subsequent spotting, which lead to an increased rate of fire spread (ROS). Currently, no such model exists. With an increased population in the rural-urban interface (or wildland-urban interface, WUI), it is also important to understand the vulnerability of houses from radiant heat and firebrand flux in order to minimise such vulnerability.

Through the testing of two models, researchers made significant inroads into providing usable outputs as well understanding various aspects of bushfire behaviour. The following are particular highlights:

1. Modelling of wind flow through tree canopies.
2. Modelling of transport of firebrands.
3. Simulations of the rate of grassfire propagation.