@conference {bnh-8275, title = {Long-range fire weather predictions developed and service established as new capability for Australia}, booktitle = {AFAC21}, year = {2021}, month = {10/2021}, publisher = {AFAC}, organization = {AFAC}, address = {Online}, abstract = {

Factors providing long-range predictability for this system include the pre-existing moisture content of vegetation (using agricultural drought measures), large-scale modes of variability (e.g., El Nino), sudden stratospheric warmings (e.g., polar vortex variations contributed to the severity of the 2019/20 summer) and long-term climate change.

The guidance products were designed with a user-driven approach, based on strong end-user engagement throughout the project. These long-range predictions are part of broader efforts to deliver seamless guidance over a wide range of time scales. Fire weather predictions and data are now available in a consistent form for long-range predictions out to several months ahead, historical records back to 1950 and future climate projections throughout this century. A seamless service across different time scales is intended to enhance planning capabilities from short to long time-scales, leading to enhanced resilience and disaster risk reduction for natural hazards. These fire weather outlooks have been described as a step change in improved capability, developed through user engagement, including for supporting risk reduction in prescribed burning and operational planning requirements.

}, keywords = {Capability, Fire, predictions, weather}, url = {https://www.afac.com.au/events/proceedings/06-10-21/article/long-range-fire-weather-predictions-developed-and-service-established-as-new-capability-for-australia}, author = {Dowdy, Andrew J} } @article {bnh-8190, title = {Soil and fuel moisture precursors of fire activity during the 2019-20 fire season, in comparison to previous seasons - Black Summer final report}, number = {686}, year = {2021}, month = {08/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {MELBOURNE}, abstract = {

Australia experienced unprecedented bushfires during the 2019-20 fire season. Millions of hectares were burned, almost 3,000 homes were destroyed, there were 26 fatalities, and communities were exposed to smoke for extended periods.\  Low soil and vegetation moisture content due to antecedent dry conditions were a key driver of fire activity.

This report extends the work in two Bushfire and Natural Hazards CRC projects to examine the 2019-20 fire season:

The national spatial datasets produced by these projects are consistent and regularly updated, separately examining soil and vegetation moisture variability, as both quantities influence fuel availability and therefore fire behaviour.

This project explores the overlaps between these data sets, as well as comparing other available data (including the Australian Landscape Water Balance) to identify atmospheric, soil and fuel moisture characteristics that contributed to fire risk during Black Summer.

Spatially coherent historical and regularly updated soil and fuel moisture datasets are critically important to fire managers so that an accurate, quantifiable assessment of potential fire activity in the landscape can be made, and this can be benchmarked against historical conditions. This information is crucial to making accurate assessments of risk and identifying situations that fall outside of historical records. One of the valuable aspects of JASMIN is that it can also be used in a predictive way and is therefore useful in anticipating soil moisture and therefore fire risk into the future in a quantitative manner on weather (short-term) and seasonal timescales. Research work in the {\textquoteright}Land Dryness{\textquoteright} project also demonstrated the capacity of soil moisture to predict future vegetation moisture content and thus more directly anticipate fire potential.

This project examines the interaction of atmospheric parameters with soil and fuel moisture content over scales of days, weeks to months, and years. Such an integration has not been undertaken previously.\ Consideration of each of these timeframes is important when making accurate assessments of fire risk. The interaction between them is also critical, as a compounding of the individual processes at the different scales occurs and this was seen in the cumulative effects of antecedent dry years, low winter rainfall and heatwaves during the Black Summer.\ 

This project examined six fire events that were nominated for investigation by the relevant jurisdictions. The fires are:

The scope of the project included examining the following:

Key findings of the project include:\ 

The findings confirm impressions of fire practitioners regarding the extremity of conditions antecedent to the 2019-20 fire season. Importantly, the datasets used in the project present a measurable and spatially coherent approach to estimating fire risk from observed and modelled soil and fuel moisture. Operational application of the datasets and approaches used here will assist in producing accurate soil and vegetation moisture forecasts for prediction of fire risk in the future.

Some immediate benefits for fire managers of this work include:

Each of the meteorological and moisture variables investigated in this study contributed useful information to an understanding of increased fire risk at each site during the 2019-20 Australian summer. Fuel moisture content provided perhaps the most immediate indicator of present fire risk. Soil moisture content permitted an assessment of future changes in fuel moisture content. Both of these integrated changes in meteorological parameters. As such, the meteorological parameters (temperature, precipitation, atmospheric moisture represented by vapour pressure) contributed an understanding of why soil and fuel moisture changed in the ways that they did and offered information on how they would change in the future. Monitoring these quantities can help fire and land managers understand how and why fire risk changes across a landscape.\ 

Future work

This project was conducted over a short time period with one objective being to establish a pathway for future research and operational application.

The following opportunities for future research with likely operational benefits have been identified:

In summary, better understanding and spatial mapping of the influence of atmospheric, soil and fuel moisture will assist fire and land managers predict fire risk, which is critical for strategic and tactical planning. Many of the recommendations could be inclusions to the Australian Fire Danger Rating System (AFDRS), and therefore of immediate benefit to fire and land managers following the introduction of the AFDRS to operational use over the next two fire seasons.

}, keywords = {black summer, Fire, fire activity, fuel, moisture, precursors, soil}, issn = {686}, author = {Paul Fox-Hughes and Marta Yebra and Shukhrat Shokirov and Vinod Kumar and Dowdy, Andrew J and Pandora Hope and Mika Peace and Sugata Narsey and Francois Delage and Huqiang Zhang} } @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-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} } @conference {bnh-3874, title = {Extreme weather: improved data products on bushfires, thunderstorms, tropical cyclones and east coast lows}, booktitle = {AFAC17}, year = {2017}, month = {09/2017}, publisher = {Bushfire and Natural Hazards CRC}, organization = {Bushfire and Natural Hazards CRC}, address = {Sydney}, abstract = {

Extreme weather events can cause a wide range of impacts on different regions throughout Australia, including costs associated with damage to natural and built environments. Effective disaster risk reduction, emergency response, infrastructure design/operation, planning and policy making all require data and information about how extreme events will change in the future.

New data products and information are currently being developed on bushfires, tropical cyclones, east coast lows and thunderstorms (including associated hazards such as extreme rainfall, winds, hail and lightning) by a project on extreme weather events in the National Environmental Science Programme \ (NESP: \ http://nespclimate.com.au/extreme-weather-projections/). \ This \ project addresses knowledge gaps on the past and future frequency and intensity of these phenomena, including the physical processes that influence the long-term variations in their characteristics, to \ produce \ practical \ tools \ and \ guidance \ products \ for \ use \ by \ planners \ and \ decision \ makers throughout Australia.

}, author = {Dowdy, Andrew J and Harvey Ye and KJ Tory and Evans, Alex and Lavender, Sally and Thatcher, Marcus and Rafter, Tony and Osbrough, Stacey and Kevin Walsh and Cavicchia, Leone and Jason P. Evans and Catto, Jennifer} } @article {BF-3546, title = {Atmospheric and fuel moisture characteristics associated with lightning-attributed fires}, journal = {Journal of Applied Meteorology and Climatology}, year = {2012}, month = {06/2012}, pages = {120604140651001}, abstract = {A systematic examination is presented of the relationship between lightning occurrence and fires attributed to lightning ignitions. Lightning occurrence data are matched to a database of fires attributed to lightning ignition over southeastern Australia, and compared with atmospheric and fuel characteristics at the time of the lightning occurrence. Factors influencing the chance of fire per lightning stroke are examined, including the influence of fuel moisture and weather parameters, as well as seasonal and diurnal variations. The fuel moisture parameters of the Canadian Fire Weather Index System are found to be useful in indicating whether or not a fire will occur, given the occurrence of lightning. The occurrence of {\textquoteleft}dry lightning{\textquoteright}, i.e. lightning which occurs without significant rainfall, is found to have a large influence on the chance of fire per lightning stroke. Through comparison of the results presented here with the results of studies from other parts of the world, a considerable degree of universality is shown to exist in the characteristics of lightning-fires and the atmospheric conditions associated with them, suggesting the potential for these results to be applied more widely than just in the area of the study.}, issn = {1558-8424}, doi = {10.1175/JAMC-D-11-0219.1}, author = {Dowdy, Andrew J and Graham A. Mills} } @article {BF-3195, title = {Characteristics of lightning-attributed wildland fires in south-east Australia}, journal = {International Journal of Wildland Fire}, year = {2012}, abstract = {Wildland fires attributed to lightning ignitions in Victoria, Australia, are examined systematically through the use of lightning occurrence data. Lightning stroke data were obtained by a network of ground-based lightning detection sensors over a 9-year period. Characteristics of these fires are examined including the temporal variability in the average chance of fire occurrence per lightning stroke and the time period from lightning ignition of a fire until the fire grows large enough to be first observed, as well as distributions of fire duration and total area burnt. It is found that the time of day that lightning occurs does not have a significant influence on the chance of fire per lightning stroke, in contrast to the time of year, for which a significant annual variation occurs. Regional variability is examined by discussing the results for Victoria, Australia, in relation to results of studies from other parts of the world.}, author = {Dowdy, Andrew J and Graham A. Mills} } @article {BF-1030, title = {Australian fire weather as represented by the McArthur Forest Fire Danger Index and the Canadian Forest Fire Weather Index.}, number = {CTR010}, year = {2009}, month = {6/30/2009}, pages = {84}, institution = {CAWCR }, type = {Technical Report}, url = {http://catalogue.nla.gov.au/Record/4614205}, author = {Dowdy, Andrew J and Finkele, K and Graham A. Mills and De Groot, W} } @article {BF-2403, title = {Index sensitivity analysis applied to the Canadian Forest Fire Weather Index and the McArthur Forest Fire Danger Index}, journal = {Meteorological Applications}, year = {2009}, month = {2009}, pages = {n/a - n/a}, abstract = {A number of different methodologies are developed for examining the sensitivities of an index. These methodologies are applied to examine the characteristics of the Canadian Fire Weather Index (FWI) and the McArthur Forest Fire Danger Index (FFDI) using 8 years of gridded data throughout Australia. Percentile changes in input conditions show that the indices are similar to each other in that they are both most sensitive to wind speed, then secondly to relative humidity and thirdly to temperature. On a finer scale, a combination of the relationship between the indices and their partial derivatives shows that the FFDI is relatively less sensitive to wind speed and rainfall, and more sensitive to temperature and relative humidity, than the FWI. A method based on equilibrium values of the indices shows that the FFDI has a temperature threshold set by recent rainfall above which its sensitivity increases, resulting in some non-linearity in its relationship with the FWI. The sensitivity differences between the indices mean that the indices are complementary in that they each respond to a somewhat different set of conditions, as is shown by examining a number of recent fire events. The fire events also reveal that index values associated with dangerous fire behaviour can vary greatly between different regions. Methods to reduce the consequences of this variation are examined, including the use of index percentiles}, doi = {10.1002/met.170}, author = {Dowdy, Andrew J and Graham A. Mills and Finkele, K and De Groot, W} }