14
BAMOS
Mar 2019
Event
summary
A decade on: lessons from Black
Saturday
Priya Mohandoss
Priya Mohandoss holds a Bachelor of Science, a Master of Journalism and a Masters of Communications
and Media Studies from Monash University.
On Tuesday 5 February, five of the nation’s fire weather experts
came together to talk about Black Saturday and the ten years
of research since then. Their findings covered topics such as
predicting fire conditions and how to respond to bushfires now
and into the future. produces enough heat energy to create its own thunderstorm.
The dangers associated with these clouds are complete
combustion from erratic winds at the surface and affected soil.
However, progress has been made since Black Saturday, where
pyrocumulonimbus clouds can now be forecast in advance.
Firstly, Dr Andrew Marshall (AMOS) held a minute’s silence for
those who perished on Black Saturday. Then moderator, Tanya
Ha (Science in Public) introduced the panel. Finally, Mika spoke on fire behaviour in downburst winds and
the potential for ember storms. She has been able to show that
turbulence around mountain ranges can accelerate fire spread
and block and move embers to produce an ember storm.
Furthermore, both these things happen late in the day, so this
can create dangerous conditions.
Professor Michael Reeder (Monash University) shared what
has been learnt in terms of extreme fire conditions from Black
Saturday. Michael presented on Wildfires and Wild Weather and
demonstrated that fire weather originates from the Atlantic
and propagates through the jet stream as Rossby Waves. Upper
level anticyclones and severe conditions are produced over
southeast Australia where the system decays.
Also, the progression of Rossby Waves the week before Black
Saturday caused temperatures to soar and allowed a cold front
to form. This was the main meteorological feature of Black
Saturday and was also responsible for ending the sequence of
heatwaves produced from Tropical Cyclone Freddy.
Michael also presented results of combining the weather
forecast information with fire monitoring using data generated
for the Kilmore East region. He discovered that spotting ahead
of the fire could indicate likely fire spread. Despite knowledge
of the ignition points, spotting is still hard to predict.
Michael’s take-home message was that in terms of extreme fire
conditions, it is key to understand cold fronts and in particular,
how they change over time as they are a driving force for fires.
Next, Dr Mika Peace (Bureau) spoke on the advances in
meteorology and understanding the link between this and fires
such as Black Saturday.
She demonstrated how satellite imagery can be used to
generate a product that can be used in real-time and become
operational in the future. She showed how smoke dispersion
associated with the Queensland fires in 2018 could be
predicted and relayed to those on ground. Furthermore, from
research done on smoke plumes in the US, responders on the
ground could be advised about increases in speed and erratic
fire behaviour.
After this, Mika talked about the Sir Ivan fire (NSW 2017) and the
effect of pyrocumulonimbus clouds. This phenomenon takes
shape in an unstable atmosphere where the fire on the surface
In terms of embers, they can be transported downwind and
start new fires. This situation happened during Black Saturday
with spotting observed 35–40 km downwind. Such findings
assist in observing fire spread, the height of plumes, burn time
and the timespan for some embers to remain alight. These
sorts of factors also depend on bark and ember quality. Yet
more importantly, it is turbulence that causes the fire to lift and
prevent them from burning downstream. This research assists
with the development of operational predictions for spotting.
Mika’s take-home message was that it is hard to know the
ignition point of a fire until the day. Also, fires are multi-
disciplinary so collaboration and community participation is
needed in order to mitigate against the impact.
Dr Paul Fox-Hughes (Bureau) says that the use of the fire danger
rating system (FDRS) was able to provide an indication of likely
fire conditions a week before and during Black Saturday. The
FDRS used at the time was the pre-existing McArthur system
consisting of three components needed to estimate the
severity of fire conditions. These are fuel type, whether weather
conditions were conducive to fire and an ignition source. This
system, formed in the1960s and developed using fire conditions
in dry eucalypt forests and grassland, was made into an index
from 1–100, where 0 was no fire and 100 was severe fire. From
this, ratings were developed from low to extreme to indicate
the potential severity of any fire. While there were gaps with this
model, it was the only FDRS that agencies had to work with for
the Black Saturday fires.
However, since then, pre-existing and present findings have
been used to implement a new Australian FDRS. The Australian
FDRS has eight fire behaviour models to allow for predictions
to be made throughout Australia, instead of it being based on
southeast Australia (which accounts for less than 25% of the
country’s landmass). Furthermore, there is a secondary level