Bushfires rage along Australian East Coast - Expert Reaction

Tuesday, 12 November 2019, 10:11 am
Press Release: Science Media Centre

Devastating bushfires along the New South Wales and Queensland coastline have caused the loss of more than 150 homes and at least three deaths.
There are more than 130 fires burning across the two states, with the number and severity of the fires prompting many to call the situation 'unprecedented' this early in the fire season.

The SMC asked experts to comment on the fires.

Dr Tara Strand, Rural Fire Research Leader, Scion, comments:

How big an area is the smoke likely to affect?

"Smoke impacts from wildfires can reach thousands of kilometres downwind and even circle the globe. Where the smoke goes depends on the smoke plume release height and the atmospheric layer the smoke enters. There are several layers in our atmosphere and each layer has different transport winds. It is these winds that determine smoke plume direction, speed, dispersion (how concentrated or diluted the plume will be) and how far downwind the smoke will travel.

"Smoke released near the ground will be influenced by terrain (i.e. down-valley flow), while smoke released from large fires, such as the ones we are seeing in NSW, will be released very high into the fast transport winds that can take a concentrated plume thousands of kilometres downwind. (As what happened the other day and is predicted by NIWA to occur again on Wednesday.) Between the smoke released near the ground to the smoke released at the top of the plume, there can be several atmospheric layers with their own transport wind properties and different layers of smoke. This is why we sometimes see smoke travelling downwind in two different directions.

"Queenstown just had a heavy smoke impact from the wildfires with ash falling from the sky. To get a smoke plume carrying ash from a wildfire that far away tells a story in itself.
It says that:
• the wildfire was/is extremely large,
• the upper air atmospheric transport winds are strong,
• the wildfire behaviour is extreme, and
• there is likely a pyro-cumulous formation (when the fire creates its own weather).
"The reason for such large particles to be transported (or even formed en-route) means that the smoke must have been emitted very high in the atmosphere into the fast trans-Tasman winds that are high above the surface. To get the smoke that high a lot of energy is needed from the wildfire, indicating a large wildfire and a lot of heat generation. This usually results in a pyro-cumulous cloud forming above the fire."

What are the dangers - both in Australia and New Zealand - from the smoke?

"Smoke - in particular, the particulate matter smaller than 2.5 micrometres (PM2.5) that makes up the majority of the smoke plume - is recognised globally as a pollutant due to its human health hazards. Particulate matter smaller than 2.5 micrometres can make it past our body's natural defences that filter out particles (i.e. the hairs in our nose) and go deep into our lung tissue and potentially into our bloodstream. Long exposure to smoke is not recommended for healthy individuals and sensitive individuals (i.e. asthmatics) need to monitor their exposure closely even in light smoke."

Are there likely to be any longer-term effects from the smoke?

"Black carbon (one of the components of PM2.5) is released from wildfires. Black carbon is known as a climate enhancer and it accelerates the melting of snow packs and glaciers when it deposits on snow or ice. For New Zealand, when the Southern Alps get impacted by smoke, this black carbon signature will be presented and this could cause accelerated melting."

How will the smoke hamper everyday life and those fighting the fires?

"As someone who lived in the wildfire-prone western USA (during university years) I can say thick smoke exposure (as seen in the Australian photographs) for days is an awful experience, your eyes smart, you can get headaches from the smoke, and you get really annoyed with the smell of smoke that permeates everywhere!

"Outdoor events are cancelled due to smoke (as happened during the Tasman fire near Nelson) such as athletic events (marathons, triathlons) as well as festivals and carnivals. In light-to-moderate smoke, the outdoor workout (jog through the park) should be turned into an indoor workout. In thick smoke, people should limit their exposure outside and try to close their houses against it.

"When these many fires are burning it could be especially difficult to avoid smoke exposure because the smoke tends to come in with most wind directions and wildfire smoke-free relief is very hard to find. Some will travel away from the wildfire smoke-prone areas but this means putting their daily lives on hold. In the case with NSW they may have to travel pretty far to avoid smoke given the number of ongoing large wildfires.

"I feel for those in what we call the 'sensitive groups' such as elderly, pregnant women, asthmatics and those with weakened immune systems, they must be especially cautious with their smoke exposure and this becomes immensely difficult in a wildfire season like what NSW is experiencing.

"Obviously drying the laundry outside is not attractive in these conditions - at a minimum, it will smell like wildfire smoke but if there is also ash-fall, black/grey dots will cover everything.

"For New Zealanders, our wildfire smoke exposure is likely to be minimal with the majority of the smoke aloft or very dilute, giving us spectacular sunrises and sunsets but no real large health impacts. But people should take caution if they feel they are impacted by smoke. The local health officer can assist with guidelines on what to do if exposed to smoke and of course, seek your GP if you feel ill or the hospital if you are having a medical emergency.

"For fire fighting smoke can slow operations. Getting aircraft near the fire is difficult in heavy smoke conditions and often aircraft end up getting grounded due to poor visibility. Smoke exposure to the firefighters is a concern and they are monitored; it is known that the greater the smoke exposure the slower the firefighters can work as their bodies are working doubly hard to deal with the smoke. Mind you - most are still in better shape than the general public so their 'slow' does not appear 'slow' to the rest of us. Firefighters are more likely to be exposed to higher concentrations (compared to the public) of other components of PM2.5 that are found in wildfire smoke, like carbon monoxide and formaldehyde, and this exposure can cause health impacts."

General comment:

"In New Zealand, we have a new smoke forecasting system that will be operational this wildfire season for wildfire authorities. This was in use as a beta-product during the Tasman fire in Nelson. The product is there to assist with smoke-based decision making (i.e. Should an outdoor activity occur, will the airport lose visibility, etc.)."

No conflict of interest declared.
Grant Pearce, fire scientist, Scion Rural Fire Research Group, comments:
"The effects of the current Australian bushfires in New South Wales and Queensland (and also again in California) are devastating and far reaching. To date, the fires have resulted in several lives being lost and many homes and properties destroyed. Here in New Zealand, the impacts have been only minor, with New Zealand firefighters gearing up for possible deployment to help out, and smoke from the Australian fires creating amazing sunsets, eerie daytime light conditions, and false smoke reports thought to have been local fire outbreaks.

"The bushfires are the result of prolonged drought conditions, which in some areas extend back several years, that have contributed to extreme drying of forests and other vegetation fuels. Grass fuels are fully cured, leaving only dead, dry brown stalks. And under the exceptionally dry conditions, all of the forest vegetation biomass present has become available to burn. This includes the larger woody branches and logs and soil organic layers, in addition to the fine leaves and twigs in the forest canopy, surface litter on the ground, and any shrub understory present. This increases the overall fuel loadings available to burn, contributing to more intense fires with greater flame lengths and energy output that are harder to control.

"On top of this, Eucalyptus species are the predominant forest trees species. These contain volatile oils which are released into the atmosphere in greater quantities as the trees become temperature and drought-stressed, raising the flammability of not only the foliage but also of the air around it. Many eucalypt species also produce flammable bark, which comes off in strips providing a perfect fuel source for embers that can burn for long periods. This can result in short-range mass ember storms and when carried to great heights by the fires’ towering convection columns, long-distance spotting that starts new fires many kilometres downwind.

"When combined with the hot, dry conditions and strong, gusty winds, these fires burn very intensely and spread extremely rapidly, producing towering pyrocumulus smoke columns that extend many kilometres into the atmosphere. The fires interact with the upper atmosphere, creating their own weather and often over-riding the other factors of terrain and surface winds that would normally drive the behaviour of smaller fires. Rising rapidly due to high-intensity burning, these convection columns can even form thunderstorms (pyrocumulonimbus, or pyroCb), producing lightning which can start more fires.

"Suppression of such fires is difficult if not impossible, due to the high fire intensities and erratic fire spread. It is too unsafe to put firefighters on the ground ahead of such fires, except in exceptional circumstances to protect lives or critical assets (where safe to do so). Any water or retardants, made even more scarce by the drought conditions, is quickly evaporated by the intense heat before it can wet the vegetation, whether applied through hoses or aircraft, even large water-bombers dropping tens of thousands of litres at a time. Firefighting becomes restricted to controlling the less intense back and flanks of the fire, getting control lines around the fire with heavy machinery, and undertaking essential property protection. In some cases, it may be possible to backburn from firebreaks or control lines out ahead to remove the fuels that feed the fire. This practice is more common in Australia, but only rarely used here in New Zealand.

"Australian fire managers have in some instances called the current fires unprecedented, in terms of the fire weather conditions under which they are burning, in how early such severe fires are occurring in the fire season, and in the number of scale and ferocity of the multiple fires burning. This is despite both NSW and Queensland (and other parts of Australia) having a long history of extreme fire events. However, the frequency of such incidents, and of severe fire seasons generally, has increased in recent years.

"Research has shown that fire risk in New Zealand will likely also increase with climate change, with a greater frequency of severe fire weather days in many parts of the country - in some cases by 2-3 times current levels. Fire seasons are also getting longer, both starting earlier and extending longer into autumn.

"This means the potential for not only more fires, but more larger fires exhibiting the sorts of extreme fire behaviour seen in Australia and California, and locally in the 2019 Nelson/Tasman and 2017 Port Hills wildfires. We are already seeing an increasing trend in New Zealand in human impacts from wildfires, especially in the rural-urban interface where urban development meets rural vegetation fuels, with more homes being destroyed or damaged, and greater numbers of people being evacuated.

"More fires also mean more wildfire smoke, with greater potential health impacts for vulnerable people, including people with respiratory conditions, and the very young and elderly. Smoke can also impact on air travel and tourism, due to particulate matter in the air, reduced visibility and air quality, as well as to the wine industry through wine taint.

"Whilst not having as severe a fire climate as Australia, or the US, due for the most part to our maritime environment, complex terrain and associated microclimates, New Zealand does still have a wildfire problem in many parts of the country (such as Marlborough and the east cost of both islands). Significant wildfires are experienced in many areas every fire season. There is also the potential for our fire climate to worsen significantly in future, bringing an increase in the number of fires, including extreme fire events such as those currently being experienced in NSW and Queensland."

Conflict of interest statement Scion’s Rural Fire Research programme is funded by the Ministry of Business, Innovation and Employment (MBIE), and receives co-funding from Fire and Emergency New Zealand, NZ Forest Owners Association/Forest Growers Levy Trust, Department of Conservation and NZ Defence Force.
Ben Noll, meteorologist, Niwa, comments:
How and why do dust/smoke clouds change the colour of the sky?

"When a beam of sunlight hits a particle in the atmosphere, something called scattering occurs. This sends some of the light’s wavelengths off in different directions and happens millions of times before that beam reaches your eye. Dust particles can help to create more scattering in the mid and upper atmosphere, which can increase the vibrancy of sunsets and sunrises. A good example occurred in Whangarei on Sunday evening.

"However, if the dust sits low in the atmosphere, it can actually have the reverse effect, leading to muted sunsets that are less colourful."

How long can we expect it to last?

"As the Australian bushfires continue to burn, plumes of smoke and dust will be continuously dispersed into the atmosphere. This will happen until the fires are put out. Since the prevailing wind direction is westerly, it is blown eastbound toward New Zealand and some of it is even making it into New Caledonia and Vanuatu."

Will it affect the South Island more than the North, or conversely?

"The next plume is due into New Zealand late Wednesday or Wednesday night, this time generally across the North Island. The trajectory of any smoke plume depends on the weather features and air flows in the Tasman Sea at the time. It takes approximately 36-48 hours from the time a plume of dust or smoke leaves Australia to reach New Zealand."

Will it negatively impact anything?

"There were some reports of dust covering vehicles in the South Island over the weekend—so maybe a car wash will be required! Those that are sensitive to fine particulates will want to take extra care by closing windows and not running their air conditioner. Given the strong winds in the New Zealand region over the next week, no dust or smoke is expected to sit over the country for a prolonged period—each plume generally takes about 12 hours to pass across a given island."
No conflict of interest.
Lewis Ferris, meteorologist, MetService, comments:
"Eastern Australia has seen an extended period of extreme heat with temperature records being broken in April 2018. Heat waves and abnormally dry periods have affected eastern areas in the last 12 months. Eastern areas had drought conditions in April so the extreme heat and already dry conditions have caused the fires to start earlier than usual.

"There has been two climate drivers which have brought about the very low amounts of rainfall.

"Firstly the Indian Ocean Dipole (IOD) has been one the strongest positive signals recorded and secondly a weak El Nino signal."
No conflict of interest.

Our colleagues at the Australian Science Media Centre gathered expert comments over the weekend. Feel free to use these comments in your reporting.
Dr Richard Thornton is CEO of the Bushfire and Natural Hazards CRC, comments:
“Unfortunately we knew, along with the fire services, that this fire season had the potential to be devastating. Our Australian Seasonal Bushfire Outlook*, released in late August, showed above normal bushfire potential along the east coast of Queensland, New South Wales, the ACT, Victoria and Tasmania, as well as parts of southern Western Australia and South Australia. Firefighters in New South Wales and Queensland have been battling severe bushfires since early September, and there’s a lot left in this fire season. This fire season is influenced by the warm and dry conditions we’ve been experiencing all year. In south east Queensland and northern New South Wales, the last three years have been dry and warm – it is these conditions that are driving the severity of the current bushfires. When preceding conditions have been like this, and the bush and grass is so dry, it doesn’t take much for a fire to get going once the wind is up. Unfortunately that is what we’ve seen, not just in recent days, but over the last few months.

"We need to start preparing now for these future risks, and not just the coming months, but the coming years and decades – we cannot keep doing things the same. No matter what we think we control, we will also need to be ready for the unexpected, and to do that we need to find a way to embrace uncertainty and plan for the inevitable. The issues are complex, and this is the role of research.

"We cannot any longer be sure of what is possible with our seasonal cycles. We need to focus on mitigation from climate change. This is an area in critical need of further research into weather prediction, land planning, infrastructure development, population trends, and community awareness. Yes, climate change is causing more severe weather, but demographic changes are having an equal impact and deserve just as much of our attention.”

No conflict of interest declared.
Dr Paul Read, bushfire, arson and climate change expert, Monash University, comments:
"Seemingly unquenchable fires down the Eastern coast are feeling increasingly unprecedented and reminiscent of some of Australia's worst, described by survivors as 'apocalyptic' 'beasts'. The most important message for those immediately affected is to remain vigilant, keep on top of escalating trends as the situation unfolds, leave early if possible, and don't overestimate your powers to fight this. Bushfires can reach temperatures hotter than a Bunsen burner at 100 metres.

"Is this situation unprecedented and how will it affect health? Apart from sheer size, another take-home message is that the fires burning since October started much earlier than usual and will get worse as Summer gets closer. I also think it will expand northwards and southwards across the whole of the Eastern seaboard.

"The number of hectares burnt can help estimate human fatalities, and here we have levels beyond this, yesterday (Friday) there were 80 fires across 370,000 hectares in NSW. Sadly I expect more deaths by dint of sheer size and, despite their best efforts, the stretching of emergency service capabilities, quite apart from burns and immediate respiratory deaths. We might need help this Summer.

"Apart from destroying life, homes and habitat, it will be affecting human, plant and animal health, even outside of the fire's path.

"An air quality index (AQI) above 300 is considered hazardous to everybody, not just the vulnerable, and usually prompts a community alert as it can lead to life-threatening medical emergencies. In the past week or two, we've already seen AQIs beyond this range in The Hunter, Central Coast, Sydney and Illawarra. Today (Sat 9) parts of Queensland have reached vast levels up to 407, much higher than most of Indonesia during last month's Borneo fires where 100,000 deaths and premature deaths were expected based on actual results in 2015. Note the words 'premature death' is of concern for all residents and not just those in the fires' direct pathways.

"What is the underlying contribution of drought and/or climate change to the intensity of the fires? To understand the role of climate change in these fires we first need to see where each and every Australian climate driver is sitting at the present moment. An anomaly outside of their combined effects, and there have already been several temperatures much higher than seasonally expected, could suggest climate change, especially if the evidence for other anomalies emerge from, for example, farmers' and firefighters' datasets alongside bureau meteorological trends. At present, we're coming out of a negative Southern Annular Mode that's caused drought from hotter West winds, so the fuel load is already crisp, and we've been getting deeper into the hot cycle of the El Nino Southern Oscillation since late 2018. On a much longer timeframe, the world is supposed to be entering a cold-snap based on the Milankovitch cycles but temperatures around the world have been knocking over records for hottest years and even decades.

"So is it climate change? Jury's always out when it comes to science, as it should be, but I'd lay bets that it is climate change affecting our seasons. And this is scary for everybody. We need to sensibly, gently (but rapidly) adjust our ways of doing economics and politics worldwide, at the same time strengthening our capacity to cope with natural and man-made disasters. Bushfires are, after all, a combination of both."

No conflict of interest declared.
David Bowman, Professor of Pyrogeography and Fire Science, and Director of the Fire Centre Research Hub in the School of Natural Sciences, The University of Tasmania, comments:
"I think the key point is that this current burst of fire activity, that builds on recent (certainly since the turn of this century) unprecedented bushfires across a broad spectrum of Australian ecosystems present a critical ‘linkage’ to understand how climate change will transform bushfire behaviour, frequency and ecological impacts. What I mean, is that we are clearly transiting away from the stage of ‘what climate models tell us about the possible effects of climate change on bushfires’ to ‘observing and experiencing extreme, unusual, and ecologically and economically damaging bushfires driven by anomalous climate conditions’. It is paramount we document (i.e. do post fire investigations of the ecological and economic impacts and climate drivers) these bushfires, as this knowledge will help use adapt to future bushfires which are set to get even more destructive.

"As a society we need a much larger and more informed discussion about bushfire adaption that is grounded in the scientific reality of these destructive events, moving beyond media sensationalism. Even though these fires are currently occurring, and people are suffering great hardships, I believe It is now timely and appropriate for a discussion of the linkage between climate change and bushfire to occur, noting we need to acknowledge uncertainties and complexities. As a society we are running out of time to adapt to climate change driven bushfires, and policy failure will lead to escalating disasters that have the capacity to eclipse the worst disasters we have experienced."

No conflict of interest declared.
Professor Ross Bradstock, Centre for Environmental Management of Bushfires, University of Wollongong, comments:
"The situation in northern NSW is unprecedented in terms of the amount active fire, extensive dryness and exposure of human communities along the coast. Thus we are seeing a tragic conjunction of circumstances that reflects decades of encroachment of urban and peri-urban development along the coast and hinterlands with resultant exposure of people and property. The disastrous 2018 fire in the coastal community of Tathra was a harbinger of things to come, not only now but into the future as our forests continue to dry under climate change. This unfortunate mix of urban and peri urban development into drying, fire prone landscapes is playing out across the world: e.g. California.

Sadly, given the weather forecast for the coming week, the crisis may worsen and extend southward into landscapes primed to burn via extreme dryness."

No conflict of interest declared.
Andrew Gissing, emergency management expert, Bushfire and Natural Hazards CRC and General Manager of Resilience at Risk Frontiers, comments:
“Severe fires have resulted in significant property damage and loss of life in the past. It is essential communities follow the messages of emergency services. Despite changes to policy following the devastating Black Saturday fires in 2009 some households remain unprepared and fail to make early decisions instead waiting for smoke or fire before making decisions to leave. Leaving early is the safest action to take.

"Risk Frontiers has estimated that nearly 1 million addresses in Australia are located less than 100 metres from bushland, putting them at the highest risk from bushfires — though not all those addresses have a house or structure on them.

"Risk Frontiers’ PerilAUS database shows that most Bushfire deaths have occurred on only nine days with the greatest loss of life occurring in the 2009 Black Saturday Bushfire.

"Climate projections estimate an increased frequency in severe Bushfire weather in the future and a lengthening of fire seasons which inevitably will put pressure on Bushfire fighting resources and communities in Bushfire prone areas. Increased use of autonomous technologies in the future could assist fire fighting efforts.

"It is likely that the fire threat in Northern NSW and South East Queensland will continue for weeks unless significant rainfall occurs assisting fire fighters to extinguish blazes.”

Conflict of interest statement: Andrew works for a private consultancy that provides research and modelling on natural disasters.
Adjunct Professor Jim McLennan, Bushfire Safety Researcher, School of Psychology and Public Health, La Trobe University, comments:
"The devastating bushfires in NSW and Queensland are unprecedented in terms of being so early going into the south-eastern Australian bushfire season, and where they are burning. These areas have rarely had intense fires because of their moist soils and vegetation. However, the fire situation is consistent with our new world of bushfire threat associated with climate change. Residents have previously not had to contend with such intense fires threatening so many locations. Levels of property preparation to resist ember attack, and household readiness to evacuate, are both likely to be lower than desirable. Local fire and emergency services personnel will be stretched to manage what is likely to be ‘new territory’ for many. Emergency management authorities will probably have to re-examine their bushfire risk mitigation plans and resourcing to adapt to this new level of threat."

No conflict of interest declared.

© Scoop Media

Science Media Centre NZ

Our aim is to promote accurate, evidence-based reporting on science and technology by helping the media work more closely with the scientific community.

The Science Media Centre is New Zealand's only trusted, independent source of information for the media on all issues related to science. Thousands of news stories providing context from and quoting New Zealand researchers have been published as a direct result of our work.

Contact Science Media Centre NZ

• Website - www.sciencemediacentre.co.nz
• Email - smc@sciencemediacentre.co.nz
• Phone - +64 4 499 5476
• Mobile - +64 21 859 365
• Facebook
• Twitter - @smcnz
• YouTube
• Postal Address - PO Box 598, Wellington 6140