@article {bnh-7342, title = {Climate Change Significantly Alters Future Wildfire Mitigation Opportunities in Southeastern Australia}, journal = {Geophysical Research Letters}, volume = {47}, year = {2020}, month = {07/2020}, abstract = {

Prescribed burning is used globally to mitigate the risks of wildfires, with severe wildfires increasing in frequency in recent decades. Despite their importance in wildfire management, the nature of future changes to prescribed burn windows under global warming remains uncertain. We use a regional climate projection ensemble to provide a robust spatiotemporal quantification of statistically significant future changes in prescribed burn windows for southeastern Australia. There are significant decreases during months presently used for prescribed burning, that is, in March to May in 2060{\textendash}2079 versus 1990{\textendash}2009 across several temperate regions. Conversely, burn windows show widespread significant increases in June to August, that is, months when burns have rarely occurred historically, and also in spring (September{\textendash}October). Overall, projected changes in temperature and fuel moisture show the most widespread and largest decreases (or increases) in the number of days within their respective ranges suitable for conducting burns. These results support wildfire risk mitigation planning.

}, keywords = {climate modeling, environmental change, Fire weather, Natural hazards, prescribed burns, risk mitigation}, doi = {https://doi.org/10.1029/2020GL088893}, url = {https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2020GL088893}, author = {Giovanni Di Virgillio and Jason P. Evans and Hamish Clarke and Jason J. Sharples and Annette Hirsch and Melissa Anne Hart} } @article {bnh-6737, title = {Deconstructing factors contributing to the 2018 fire weather in Queensland, Australia}, volume = {101}, year = {2020}, month = {02/2020}, pages = {S15-S21}, edition = {1}, abstract = {

Factors including the circulation pattern and antecedent conditions contributed to 2018 northeast Australian fires. High background temperatures also played a role for which model evidence suggests an anthropogenic influence.

}, keywords = {Fire, Fire weather, Queensland}, doi = {10.1175/BAMS-D-19-0144.1}, url = {https://www.ametsoc.org/ams/index.cfm/publications/bulletin-of-the-american-meteorological-society-bams/explaining-extreme-events-from-a-climate-perspective/}, author = {Sophie Lewis and Stephanie Blake and Blair Trewin and Mitchell Black and Dowdy, Andrew J and Sarah Perkins-Kirkpatrick and Andrew King and Jason J. Sharples} } @article {bnh-7773, title = {Pyrocumulonimbus Firepower Threshold: Assessing the atmospheric potential for pyroCb}, journal = {Weather and Forecasting}, year = {2020}, month = {12/2020}, abstract = {

Pyrocumulonimbus (pyroCb) clouds are difficult to predict and can produce extreme and unexpected wildfire behaviour that can be very hazardous to fire crews. Many forecasters modify conventional thunderstorm diagnostics to predict pyroCb potential, by adding temperature (Δθ) and moisture increments (Δq) to represent smoke plume thermodynamics near the expected plume condensation level. However, estimating these Δθ\ and Δq\ increments is a highly subjective process that requires expert knowledge of all factors that might influence future fire size and intensity. In this paper, instead of trying to anticipate these Δθ\ and Δq\ increments for a particular fire, the minimum firepower required to generate pyroCb for a given atmospheric environment is considered. This concept, termed the PyroCb Firepower Threshold (PFT) requires only atmospheric information, removing the need for subjective estimates of the fire contribution.

A simple approach to calculating PFT is presented that incorporates only basic plume-rise physics, yielding an analytic solution that offers important insight into plume behaviour and pyroCb formation. Minimum increments of Δθ\ and Δq\ required for deep, moist convection, plus a minimum cloud-base height (Zfc), are diagnosed on a thermodynamic diagram. Briggs plume rise equations are used to convert Δθ,\ Zfc, and a mean horizontal windspeed (U) to a measure of the PFT: the minimum heat flux entering the base of the plume. This PFT is proportional to the product of\ U, Δθ, and the square of\ Zfc. Plume behaviour insights provided by the Briggs equations are discussed, and a selection of PFT examples presented.

}, keywords = {atmosphere, fire power, Fire weather, meteorology, pyrocumulonimbus}, doi = {https://doi.org/10.1175/WAF-D-20-0027.1}, url = {https://journals.ametsoc.org/view/journals/wefo/aop/WAF-D-20-0027.1/WAF-D-20-0027.1.xml}, author = {KJ Tory and Jeffrey Kepert} } @article {bnh-5654, title = {Climate change effects on the frequency, seasonality and interannual variability of suitable prescribed burning weather conditions in south-eastern Australia}, journal = {Agricultural and Forest Meteorology}, volume = {271}, year = {2019}, month = {06/2019}, chapter = {148-157}, abstract = {

Despite the importance of prescribed burning in contemporary fire management, there is little understanding of how climate change will influence the weather conditions under which it is deployed. We provide quantitative estimates of potential changes in the number of prescribed burning days in coastal NSW in south-eastern Australia, a fire-prone area dominated by dry sclerophyll forests. Burning days are calculated from an objectively designed regional climate model ensemble using three definitions of suitable weather conditions based on: a literature search (Literature), actual weather observed during recorded prescribed burns (Observed) and operational guidelines (Operational). Contrary to some claims, evidence for a decrease in prescribed burning days under projected future climates is weak. We found a complex pattern of changes, with the potential for substantial and widespread increases in the current burning seasons of autumn (March-May) and spring (August-October). Projected changes were particularly uncertain in northern NSW, spanning substantial increases and decreases during autumn. The magnitude of projected changes in the frequency of burning days was highly sensitive to which definition of suitable weather conditions was used, with a relatively small change for the Operational definition (+0.3 to +1.9 days per year across the study area) and larger ranges for the Observed (+0.2 to +7.9 days) and Literature (+1.7 to +6.2 days) definitions. Interannual variability in the number of burning days is projected to increase slightly under projected climate change. Our study highlights the need for a better understanding of the weather conditions required for safe and effective prescribed burning. Our analysis provides practitioners with quantitative information to assess their exposure to a range of potential changes in the frequency, seasonality and variability of prescribed burning weather conditions.

}, keywords = {Burn window, Climate change, Fire weather, Global warming, Hazard reduction, Prescribed burning, prescribed fire}, doi = {https://doi.org/10.1016/j.agrformet.2019.03.005}, url = {https://www.sciencedirect.com/science/article/pii/S0168192319301091}, author = {Hamish Clarke and Bruce Tran and Matthias M. Boer and Owen Price and Belinda Kenny and Ross Bradstock} } @article {bnh-7478, title = {Climate Change Increases the Potential for Extreme Wildfires}, journal = {Geophysical Research Letters}, volume = {46}, year = {2019}, month = {07/2019}, pages = {8517-8526}, abstract = {


Pyrocumulonimbus (pyroCb) wildfires cause devastation in many regions globally. Given that fire-atmosphere coupling is associated with pyroCbs, future changes in coincident high index values of atmospheric instability and dryness (C-Haines) and near-surface fire weather are assessed for southeastern Australia using a regional climate projection ensemble. We show that observed pyroCb events occur predominantly on forested, rugged landscapes during extreme C-Haines conditions, but over a wide range of surface fire weather conditions. Statistically significant increases in the number of days where both C-Haines and near-surface fire weather values are conducive to pyroCb development are projected across southeastern Australia, predominantly for November (spring), and less strongly for December (summer) in 2060-2079 versus 1990-2009, with future C-Haines increases linked to increased 850-hPa dewpoint depression. The increased future occurrence of conditions conducive to pyroCb development and their extension into spring have implications for mitigating these dangerous wildfires and urbanizing fire-prone landscapes.

}, keywords = {atmospheric instability, dewpoint depression, Fire weather, Natural hazards, pyrocumulonimbus, regional climate modeling}, doi = {https://doi.org/10.1029/2019GL083699}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL083699}, author = {Giovanni Virgilio and Jason P. Evans and Stephanie Blake and Matthew Armstrong and Dowdy, Andrew J and Jason J. Sharples and McRae} } @article {bnh-6392, title = {Evolution of an extreme Pyrocumulonimbus-driven wildfire event in Tasmania, Australia}, journal = {Natural Hazards and Earth System Sciences}, year = {2019}, month = {12/2019}, abstract = {

Extreme fires have substantial adverse effects on society and natural ecosystems. Such events can be associated with intense coupling of fire behaviour with the atmosphere, resulting in extreme fire characteristics such as pyrocumulonimbuscloud (pyroCb) development. Concern that anthropogenic climate change is increasing the occurrence of pyroCbs globally is driving more focused research into these meteorological phenomena. Using 6-minute scans from a nearby weather radar, we describe the development of a pyroCb during the afternoon of 4 January 2013 above the Forcett-Dunalley fire in south-eastern Tasmania. We relate storm development to: (1) near-surface weather using the McArthur Forest Fire Danger Index (FFDI), and the C-Haines Index, a measure of the vertical atmospheric stability and dryness both derived from gridded weather reanalysis for Tasmania (BARRA-TA), and (2) a chronosequence of fire severity derived from remote sensing. We show that the pyroCb rapidly developed over a 24-minute period in the afternoon of 4 January, with the cloud top reaching a height of 15 km. The pyroCb was associated with a highly unstable atmosphere (C-Haines 10-11) and Severe-marginally Extreme (FFDI 60-75) near-surface fire weather, and formed over an area of forest that was severely burned (total crown defoliation). We use spatial patterns of elevated fire weather in Tasmania, and fire weather during major runs of large wildfires in Tasmania for the period 2007-2016 to geographically and historically contextualise this pyroCb event. Although the Forcett-Dunalley fire is the only known record of a pyroCb in Tasmania, our results show that eastern and south-eastern Tasmania are prone to the conjunction of high FFDI and C-Haines values that have been associated with pyroCb development. Our findings have implications for fire weather forecasting and wildfire management, and highlight the vulnerability of southeast Tasmania to extreme fire events.

}, keywords = {C-Haines, extreme fire, fire severity, Fire weather, McArthur Forest Fire Danger Index, pyrocumulonimbus, smoke plume injection, Tasmania, wildland fire}, doi = {https://doi.org/10.5194/nhess-2019-354}, url = {https://www.nat-hazards-earth-syst-sci-discuss.net/nhess-2019-354/}, author = {Mercy Ndalila and Grant Williamson and Paul Fox-Hughes and Jason J. Sharples and David Bowman} } @conference {bnh-6411, title = {Fire weather and prototype fire danger ratings for the Gell River fire, Tasmania}, booktitle = {Bushfire and Natural Hazards CRC Research Day AFAC19}, year = {2019}, month = {12/2019}, address = {Melbourne}, abstract = {

We provide a preliminary analysis of the meteorology of key aspects of the Gell River fire in Tasmania during late December 2018 and early January 2019, including the lightning storm that ignited the fire, and conditions on 4 January 2019, when the fire increased substantially in size. We also briefly assess the performance of the Australian National Fire Danger Rating System (AFDRS) Research Prototype available on 4 January against observations of fire spread and routine McArthur Forest Fire Danger forecasts.

The Gell River fire occurred within a context of declining October {\textendash} April rainfall in western Tasmania over the last two decades, in comparison to the average rainfall for the period since 1900 (Fig. 1, Bureau of Meteorology and CSIRO (2018)). It was one of several large fires that competed for fire management resources over an extended period during the 2018-2019 Tasmanian fire season. The fire impacted natural values including those of the Tasmanian Wilderness World Heritage Area (TWWHA) and risked spreading into parts of the iconic Mt Field National Park, as well as threatening a number of communities in the Derwent Valley, particularly Maydena. The Gell River fire also threatened major electrical transmission infrastructure connecting the large Gordon-Pedder power generation facility in the west of Tasmania to population centres in the east, and burnt approximately 500 ha of a 5,000 ha pine plantation. On 4 January, thick smoke from the fire crossed over the Greater Hobart area, sparking concern and raising awareness within the wider community about the fire activity (Fig. 2).

}, keywords = {Fire behaviour, Fire weather, modelling}, url = {https://knowledge.aidr.org.au/resources/australian-journal-of-emergency-management-monograph-series/}, author = {Paul Fox-Hughes and Stuart Matthews and Chris Collins and Saskia Grootemaat and Jennifer J Hollis and Alexander Holmes and Belinda Kenny and John Runcie and Samuel Sauvage} } @article {bnh-6332, title = {Firefighter tenability and its influence on wildfire suppression}, journal = {Fire Safety Journal}, volume = {106}, year = {2019}, month = {06/2019}, pages = {38-51}, abstract = {

This paper provides analysis of international fire service siege wildfire suppression thresholds and reports on the effect of forest fuel structure, fire weather condition and terrain on the suitability of suppression strategies. Further, this study applies a fire engineering approach whereby siege wildfire behaviour is deterministically assessed against firefighter tenability thresholds. This research is significant as it is the first study to consider human tenability as a factor in determining appropriateness of wildfire suppression strategies and tactics. The results clearly demonstrate offensive siege wildfire suppression involving direct head fire attacks by personnel and appliances exposes firefighters to untenable conditions well in advance of the head fire edge. Accordingly fire services may need to consider earlier instigation of defensive strategies and increased reliance on aerial wildfire suppression.

}, keywords = {fire engineering, Fire weather, fuel, suppression thresholds, Wildfire}, doi = {https://doi.org/10.1016/j.firesaf.2019.03.012}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0379711218303515}, author = {Greg Penney and Daryoush Habibi and Marcus Cattani} } @conference {bnh-6398, title = {Science in operations: QFES response to the 2018 Queensland fires}, booktitle = {Bushfire and Natural Hazards CRC Research Day AFAC19}, year = {2019}, month = {12/2019}, address = {Melbourne}, abstract = {

In late November 2018, Queensland experienced an unprecedented fire event, with more than 1,000 bushfires burning across the state. Fire weather conditions peaked on Wednesday 28 November, with {\textquoteright}Catastrophic{\textquoteright} fire danger observed at Rockhampton Airport for over three hours. Over 1 million hectares of land were burnt, 479 post-fire damage assessments were completed, with nine homes destroyed and a further eight damaged .Queensland Fire and Emergency Services (QFES) requested national resources to support both tactical firefighting and operational roles. In anticipation of forecast conditions on 28 November, QFES Manager of Predictive Services, Fire Behaviour Analyst (FBAN) Andrew Sturgess requested Bureau of Meteorologist (BoM) meteorologist and Bushfire and Natural Hazards Cooperative Research Centre (CRC) researcher Mika Peace provide support to the State Operations Centre FBAN team. In this paper, we share our personal experiences and reflections as well as those of the FBAN team. In summary, we consider how the Queensland learnings may inform future events. Challenges include resourcing to develop teams with the appropriate capabilities and the ability to identify extreme conditions in advance.

}, keywords = {Fire weather, multidisciplinary, operations}, url = {https://knowledge.aidr.org.au/resources/australian-journal-of-emergency-management-monograph-series/}, author = {Andrew Sturgess and Mika Peace} } @article {BF-4282, title = {A comparison of the fire weather characteristics of the Melbourne dust storm (1983) and Black Saturday (2009): a high-resolution ACCESS case study}, journal = {20th International Congress on Modelling and Simulation}, year = {2013}, month = {12/2013}, pages = {167-172}, chapter = {167}, abstract = {We present the results of high-resolution simulations of the fire weather over Melbourne during its notorious dust storm on 8 February 1983. The simulations were performed using the Australian Community Climate and Earth-System Simulator (ACCESS), and involved a sequence of nested model runs starting with a global model run initialised with an ERA-Interim reanalysis initial condition. The ACCESS model is used at the Bureau of Meteorology for operational numerical weather prediction, but is used here in research mode at resolutions much finer than those currently used operationally. The day of the dust storm saw the passage of a significant cool change across Victoria, with many similarities in the simulations to that of Black Saturday (7 February 2009), against which we compare it. Wind changes such as these two can have a significant (and dangerous) impact on the behaviour of bushfires in southeast Australia, and their prediction forms an important component of fire weather prediction in this part of the country. While the wind change on 8 February 1983 was accompanied by some fire activity, that activity was much less than the major fire activity which accompanied the significant wind change eight days later on Ash Wednesday (16 February 1983). Why the dust storm wind change was not associated with severe fires, while those on Ash Wednesday and Black Saturday were, is a challenging question. Catastrophic fires are quite rare, whereas significant fire weather events that could potentially lead to catastrophic fires (if the non-meteorological prerequisites were to fall into place) are much more common and their study can lead to further understanding of the fire events.}, keywords = {Ash Wednesday, Black Saturday, Fire weather, Melbourne{\textquoteright}s dust storm, numerical weather prediction}, url = {http://www.mssanz.org.au/modsim2013/A3/fawcett.pdf}, author = {Robert Fawcett and Alan Wain and W. Thurston and Jeffrey Kepert and KJ Tory} }