Australia’s fire services mitigate the risk to the community from wildfires in a manner that leaves minimal
residual risk. This work is founded on forecasts of fire behaviour based on fuel, terrain and weather. Using
steady-state fire behaviour equations, any given set of conditions permits a single expected fire behaviour
prediction. Since 2001, Australia has been impacted with rapidly increasing frequency by a class of fires
driven by a coupling of the fire with the atmosphere above the mixed layer. In their most extreme form, these
fires produced pyroCbs. The continental climatology has four events in the satellite era up to 2001, but since
then 56 further confirmed events. This change in frequency is considered to be due to climate change. Blowup
events were seen to occur when a fire fire switches from normal linear flaming to areal flaming - over 5km
flaming depth has been observed. If this happens in an unstable atmosphere, the plume forms a cloud before
it mixes out. The latent heat of condensation then released allows a rapid escalation of fire intensity on the
surface. Arising from the extreme wildfires that hit Canberra on 18 January 2003, a series studies have shown
how these fires develop. These insights were used to develop a predictive model for these events. The Blow
Up Fire Outlook (BUFO) model incorporates these in a process model that has been formally trialled. An
extreme wildfire is defined here as one where one or more blow-up events occur before it is suppressed. Deep
flaming events are known to be caused by: two steady-state processes (strong winds and wind changes), a set
of dynamic processes (vorticity-driven lateral spread, eruptive spread, dense spotting), inappropriate use of
ignition devices, and reburning of areas as new fuel becomes flammable with time. The BUFO model was
run in trial mode in the Australian Capital Territory and New South Wales over three summers. The results
indicated that the trial was successful, despite the small sample size involved. The POD was 100%, the FAR
was 33% and the TNR was 100%. The model utilised weather forecast data from the Bureau of Meteorology,
weather observations, terrain analysis data from the HighFire Risk project (www.highfirerisk.com.au) and
fire information. It makes heavy use of remotely-sensed information. The model is designed to start if there
is an uncontained wildfire with raised fire danger, and to ask questions that are either true or false. The
answers form a path that either loops back (for the model to be re-run at a different time) or yields a prediction
of the potential for a blow-up fire event. Most of the nine questions are required to assess the potential for the
formation of deep flaming. So, given that most of the damage is caused by fires not covered by the standard
toolbox used by fire services, BUFO is designed to augment the work of Fire Behaviour Analysts. We are
working to increase its uptake across the sector.