9th Short Course on Fire Behaviour

Short bio: Albert Simeoni is a professor and the Department Head of Fire Protection Engineering at Worcester Polytechnic Institute. He received his education in France, obtaining a Bachelor Degree in Physics from the University of Corsica (1994), a Master Degree in Mechanical Engineering from the University of Aix-Marseille (1996), and a Ph.D. in Physics from the University of Corsica (2000). He is an expert in wildland fire and fire science. He has experience in developing experimental, analytical, and numerical techniques to better understand fire dynamics and to predict fire and wildland fire behavior and impact. Before joining WPI, he held academic leadership positions in fire research in the UK (university of Edinburgh) and in France (university of Corsica). He has also experience as a consultant in fire science in the US and has spent over 10 years volunteering as a firefighter in France, eventually becoming Fire Captain and chief of a small Fire Station.

Preliminary programme

Speakers

Abstract: Nowadays, everybody is aware of the enormous and still growing impact of wildfires all around the world. Extreme fires occur more frequently than ever and the cost of wildfires and Wildland Urban Interface (WUI) fires seems to have no ceiling. To help mitigate the effects of these fires on people, property and the environment, an increasing knowledge in fire behavior is needed. It will allow developing a better understanding of the factors that drive fire dynamics and fire impact in a constantly changing environment. This lecture introduces the basic principles governing fire behavior, as well as different approaches related to its study. The fundamental heat and mass transfer mechanisms of fire spread and the combustion stages undergone by burning vegetation are presented. In addition, the parameters driving fire spread are detailed, including fuel moisture content, fuel distribution, slope and wind. Different forms of extreme fires are also presented along with their basic behavior. Then, different modeling and experimental approaches are described, from the laboratory to the field scale. These approaches are commonly used to better understand and represent fire behavior, but also to estimate risk, to predict fire spread and impact, or to propose mitigation solutions. Finally, a general approach to the study of fire behavior is presented along with its associated challenges and needed areas of improvement.

Short bio:

Abstract: (Two part lesson) Despite decades of attempts to model wildland fire spread, there is still a distinct lack in understanding of the underlying physical processes. To resolve these limitations, laboratory experiments are critical and should provide the foundation of future modeling efforts. Laboratory and field research is presented concerning processes of convective heat transfer, energy release, and ignition occurring in wildland fires. Specialized apparatus and measurements have been developed to explore how flame structure affects heating of fuel materials in combinations of wind, slope, flame source dimensions, and orientation of the flame front. Fuel materials arranged in highly controlled configurations are burned to understand the important variables affecting heat release and duration for fuel particles and beds. Convection and radiation heating experiments of fuel particles having different geometries are used to demonstrate the relative contributions of heat transfer processes to ignition of fuel materials. All processes are essential components of the coupled fire spread system and can be linked by modeling to examine their complex interactions at a high spatial and temporal resolution.

Short bio: Sara McAllister earned her Ph.D. in Mechanical Engineering from the University of California, Berkeley. Since 2009, she has been a Research Mechanical Engineer with the U.S. Forest Service at the Missoula Fire Sciences Laboratory in Missoula, Montana. As part of the National Fire Decision Support Center, Sara’s research focuses on the fundamental governing mechanisms of wildland fire spread. Specifically, her research includes understanding the critical conditions for solid fuel ignition, flammability of live forest fuels, ignition due to convective heating, and fuel bed property effects on burning rate. She has authored a textbook on combustion fundamentals, co-authored a textbook on wildland fire behavior, and over 80 peer-reviewed publications and conference papers. In her spare time, Sara enjoys cycling, running, and racing in triathlons.

Abstract: (Two part lesson) Despite decades of attempts to model wildland fire spread, there is still a distinct lack in understanding of the underlying physical processes. To resolve these limitations, laboratory experiments are critical and should provide the foundation of future modeling efforts. Laboratory and field research is presented concerning processes of convective heat transfer, energy release, and ignition occurring in wildland fires. Specialized apparatus and measurements have been developed to explore how flame structure affects heating of fuel materials in combinations of wind, slope, flame source dimensions, and orientation of the flame front. Fuel materials arranged in highly controlled configurations are burned to understand the important variables affecting heat release and duration for fuel particles and beds. Convection and radiation heating experiments of fuel particles having different geometries are used to demonstrate the relative contributions of heat transfer processes to ignition of fuel materials. All processes are essential components of the coupled fire spread system and can be linked by modeling to examine their complex interactions at a high spatial and temporal resolution.

Short bio: Prof. Naian Liu graduated from USTC, getting his PhD degree of thermo-physics in 2000. Then he was employed in USTC as a lecturer at SKLFS and in 2004 promoted to be an associate professor there. In 2007 he was promoted to be a professor at SKLFS of USTC. He was elected to be the Vice Director of SKLFS in 2008. He was selected to be a visiting scholar at the University of Tokyo in 2000, and at the Hong Kong Polytechnic University in 2004. Prof. Naian Liu is the Vice Director and professor of the State Key Laboratory of Fire Science (SKLFS) at the University of Science and Technology of China (USTC). He is also the chief of the Division of Wildland and Urban Fires of SKLFS. The Division develops, verifies, and utilizes experiments and models to quantify the behavior of wildland (forest, grassland and brush) fire and urban fire, and develop the means to reduce the impact of the wildland and urban fires on people, property, and the environment.

Short bio: Full Professor at the Department of Mechanical Engineering of the Faculty of Science and Technology of the University of Coimbra, in Portugal (retired). D. Viegas has a PhD in Aerodynamics and worked initially on wind engineering and industrial aerodynamics, in 1985 started to work in the area of forest fires performing research activity in the fields of fire propagation and fire safety. In 1997 he created the Forest Fire Research Laboratory (LEIF) that is a unique asset of its kind in Europe and one of the best equipped in the World for the research on physical aspects of fire spread. D. Viegas participated in more than sixty research projects in the field of forest fires, half of them with European funding. He coordinated more than 40 projects and contracts with Stakeholders in the field of forest fires. He was the Supervisor of several Doctoral Thesis and also Co-supervisor with other Portuguese and international research groups in this area of research. He has been invited to integrate PhD Juris at international level, in Spain, France, United Kingdom, Australia, Switzerland, Finland, Germany and Italy. He was an expert called by the Court to report on accidents with fire fighters or on Large fires in Portugal in 2005 and 2006, Spain in 2005, Australia in 2011 and Israel in 2015. He was an Expert called by the Portuguese National Assembly to report on the situation of Forest Fires in Portugal in 2003 and 2013 and he was a member of the Enquiry Committee designated by the Government to investigate accidents and large fires in Portugal in 2006, 2012 and 2013 and in Croatia in 2007. By invitation of the Ministry of Internal Administration, he was the coordinator of the study on the large forest fire occurred in 2012 in the Algarve, the study on the two major forest fires occurred in 2013 and the fatalities that occurred in that year and also the study on the fire of Pedrógão Grande in June 2017, the study on the fires of October 15, 2017, and a fatal accident that occurred in July 2020. Since 2018 he is a member appointed by the National Parliament to the Technical Independent Observatory for fires, that supports the Portuguese Agencies in assessing the implementation of policies to manage forest fires.

Abstract:The concepts of Extreme Wildfire Event and Extreme Fire Behaviour are presented. The limitations of current fire behaviour modelling based on the triangle of fire factors are exposed as well as the need to consider explicitly the time dependence in the dynamic behaviour of a fire, due to the interaction of the fire and the surrounding environment. Some modes of extreme fire behaviour, like eruptive fires, junction fires, spot fires and fire whirls are described and analyzed. The canonic cases of a point ignition fire in a slope, in a canyon and in the junction of two fire lines are presented, to illustrate the concepts of intermittent and oscillatory fire behaviour. An overall perspective of fire acceleration and deceleration is proposed.

Short bio: Dr. Craig Clements is Professor and Chair in the Department of Meteorology and Climate Science at San José State University and Director of the National Science Foundation I/UCRC Wildfire Interdisciplinary Research Center. He leads research on fire weather, extreme fire behavior, fire-atmosphere interactions, and conducting wildfire field experiments. Dr. Clements has published over 50 peer-reviewed journal articles and teaches courses in Fire Weather, Wildfire Science, Mountain Meteorology, Climate Change, and Meteorological Instrumentation. He received his PhD in Geophysics from the University of Houston, his MS in Meteorology from the University of Utah, and a BS degree in Geography from the University of Nevada.

Abstract:As wildfires are becoming more extreme across the globe, the role of the interactions between the fire and the atmosphere is becoming more relevant.This course will explore fire-atmosphere interactions at multiple scales starting with the micrometeorological scale of turbulence and how that is measuredin the field. The course will then explore large wildfires and how plume dynamics affects atmospheric coupling and impact on fire behavior. Topics willinclude turbulence and turbulence spectra of the fire environment, sensible and latent heat fluxes, fire-induced circulations, and updraft and verticalvelocity structures of both ordinary plumes and pyrocumulonimbus. Studies using both coupled fire-atmosphere modeling and observational methods willbe described and used to illustrate these phenomena and how we can better understand extreme events. Finally,challenges of observing extremewildfires and their associated meteorology are discussed as well as needed areas of improvement.

Short bio: Chris Lautenberger is a Fire Protection Engineer based in Northern California with expertise in fire science, fire dynamics, fire modelling, and forensic fire reconstruction. He holds a PhD in Mechanical Engineering from the University of California at Berkeley where he majored in combustion and studied pyrolysis and solid-phase combustion. Chris currently leads a project funded by the California Energy Commission to develop next-generation wildland fire spread and risk models. He has co-taught Masters-level courses in Fire Dynamics and Fire Modeling in the Department of Fire Protection Engineering at California Polytechnic State University, San Luis Obispo.

Abstract: This presentation addresses methodologies for modeling landscape-scale fire risk – defined as the product of probability and consequence – with an emphasis on fire behavior modeling. First, approaches to quantifying fire occurrence (probability) and fire impacts to high value resources and assets (consequence) will be explained. Techniques to compute climatological fire risk using fire behavior modeling under both historical and climate adjusted / mid-century weather streams will be reviewed. Related techniques for quantifying near-term (up to 5-days lead time) fire risk under forecasted wind and weather conditions will also be explained. Due to the disproportionate large role that powerline-caused ignitions have played in recent damaging/large-loss fires, newly developed approaches to quantifying risk from powerline caused fires will be explained. The final part of the presentation will address limitations of current operational fire behavior models used in risk modeling such as lack of fire/atmosphere coupling, limited ability to account for suppression activities, and inability to model spread in built up / urban wildland urban interface areas, including the ramifications of these caveats on modeled risk levels.

Short bio:Dr. Rodman Linn is a senior scientist a in the Earth and Environmental Sciences Division at Los Alamos National Laboratory (LANL) and the Associate Director for Fire Science for the WIFIRE lab at UC San Diego. Dr. Linn leads LANL efforts to use next-generation process-based wildfire models for the study of fundamental wildfire behavior, evaluation of prescribed fire tactics, understanding influences of complex environmental conditions on fire behavior and wildfire’s interaction with other landscape disturbances such as insects or drought. For over two decades, he has served as principal investigator for a process-based coupled fire/atmosphere model, FIRETEC. Dr. Linn is the co-lead developer of the fast-running coupled fire-atmosphere model QUIC-Fire.

Abstract: A combination of climate change and a century of reactionary fire suppression has led to fuel accumulation, flammable forest structure, and ultimately, conditions that are conducive to high-intensity and frequently-destructive wildfires in many parts of the world. Members of wildland fire science and management communities postulate that the solution is not just better response to wildfires, but should include employment of more aggressive proactive measures. Such proactive measures, including fuel treatments and prescribed fires, can help address emerging wildland fire challenges by reducing risk and promoting ecosystem sustainability.
Tools intended to support prescribed fire planning have different requirements from those primarily designed for rapid response. For example, prescribed fire planning tools do not have the same types of run time or computational constraints as tools used for response-oriented applications. However, a tool that is being used for planning or optimization has more value if it can be run for the range of possible conditions that might be present on burn day. Prescribed fire planning tools need to explicitly capture the dynamic coupling between fires an surrounding atmosphere and the influence of vegetation structure, which can be dynamic as vegetation is consumed. Prescribed fire tools also need to be able to represent the influences of complex and transient ignition patterns that are used by practitioners to engineer the fire and smoke behavior to meet burn objectives and constraints. As interest towards application of prescribed fire to meet fire risk management and ecosystem security objectives increases, it will be important to look beyond current response-oriented fire spread modeling capabilities. However, these new capabilities will inherently require different kinds of data such as three-dimensional vegetation structure as inputs for emerging models.

Short bio: Eulàlia Planas, PhD, Associate Professor at the chemical engineering Department of the Universitat Politècnica de Catalunya (UPC). Head of the Centre for Technological Risk Studies (CERTEC, https://certec.upc.edu/en) and UPC Coordinator of the International Master of Science in Fire Safety Engineering (IMFSE, https://imfse.be/). Her main research lines are the study of hydrocarbon pool-fires and jet-fires; the mathematical modelling of major accidents; risk analysis in the transportation of hazardous materials; and the study of wildfires. In the field of wildfire research, she has developed infrared image processing systems to quantify fire progression (rate of spread, fire intensity, and flame geometry) and aerial fire attack effectiveness. She has also worked on providing systems to deliver fire behaviour forecasts for decision-making, based on data assimilation and inverse modelling. Currently she develops methodologies based on CFD modelling to study the effects of burning residential fuels on structures, relying on performance-based criteria to assess houses vulnerability and sheltering capacity. Prof. Planas is also involved extensively on experimental fire research.

Abstract: Fire affecting Wildland-Urban Interface (WUI) communities have increased rapidly over the past few decades, in both frequency and severity, and the number of structures lost each year has increased significantly worldwide (Caton et al., 2017). Consequently, in Europe, fires approaching WUI settlements have also become a growing problem (Pastor et al., 2020; Badia et al., 2019; Mitsopoulos et al, 2020; D’Este et al, 2021). Due to global warming, the hot and dry seasons in southern Europe are lengthening and forest fires are now more intense and more destructive [Jolly et al, 2015, Ganteaume et al., 2021]. Other consequences of climate change include the emergence of new WUI fire-prone areas in northern countries, which generally do not have policies and communities designed and adapted to deal with large wildfires. In addition, European forests are experiencing a growing human pressure, with a significant increase in urbanization and therefore in ignition sources at the WUI too (Paveglio et al., 2015; Wigtil et al, 2016). When urban settlements are exposed to extreme wildfire conditions, many homes can ignite simultaneously, completely overwhelming firefighters’ ability to cope, thus reducing the fire protection effectiveness (Cohen, 2008; Ronchi et al., 2019). This has led to a growing need for self-protection and therefore for the creation of fire-adapted communities, which can safely coexist with wildfires (Vacca et al., 2020; Kuligowski, 2021). The WUI fire problem is inherently complex, as it is characterized by the interaction of multiple phenomena of diverse nature occurring at different observation scales: the macroscale or landscape scale, the mesoscale or settlement scale and the microscale or homeowner scale. All three are interrelated and need to be taken into account when studying WUI fire phenomena, which has to be tackled with an interdisciplinary approach (Bento-Gonçalves & Vieira, 2020; Vacca et al., 2022). In this lecture, a review of the WUI fire problem in Europe from diverse perspectives is done highlighting the current research state of the art and the existing gaps of knowledge whose answer could help improving prevention and mitigation strategies.

Short bio: Dr. Eric Link is a researcher in the WUI Fire Group of the Fire Research Division at the National Institute of Standards and Technology. Since joining NIST in 2017, he has focused on the WUI fire problem in the U.S. through post-fire case studies and field data collection, working to compile knowledge to inform the fire service, communities, policymakers, and homeowners about WUI fires, fire response, and mitigation to improve preparedness and resiliency. Dr. Link earned degrees in Fire Protection Engineering (BS, MS) and Mechanical Engineering (PhD) from the University of Maryland, College Park, where he researched fire sprinkler sprays and fire suppression.

Abstract: Over the last 5 years the United States has experienced a number of massive, destructive, and deadly wildland-urban interface fires. In the state of California, 13 of the 20 most destructive WUI fires have occurred since 2017, including the most destructive. The Camp Fire destroyed over 18000 structures and killed 85 civilians in November 2018. With abundant data sources available, an in-depth case study was initiated after the Camp Fire to learn from such an impactful event. A detailed reconstruction of the incident was established. Over 2200 individual fire observation datapoints were integrated into a fire progression timeline, encompassing the rapid development and spread of the fire, long-range spotting behavior, and structure ignitions. The fire progression timeline, in turn, supported additional in-depth study of life safety and evacuation aspects of the incident. Significant findings regarding the evacuation notification timeline with respect to fire progression, the extensive use of temporary refuge areas, and the number of civilian rescues will be explored. A number of other western states have since experienced their own most destructive fires, including the Almeda Fire (Oregon, 2020; >2600 structures), Marshall Fire (Colorado, 2021; >1000 structures), and the Calf Canyon/Hermits Peak Fire (New Mexico, 2022; >900 structures); the list of other significant fires in this time period is extensive. Common themes visible in many recent WUI fires include high winds and dry fuels, significant structure involvement and contribution to fire spread, and short-fuse community and regional evacuations. Aspects and implications of the Camp Fire case study regarding structural fire mitigation, community evacuation hazards, and preparedness planning are applicable to a wide range of WUI fire incidents.

Short bio: Jason Sharples is Professor of Bushfire Dynamics and Director of the UNSW Bushfire Research Group in the School of Science, UNSW Canberra. He has led several Australian Research Council (ARC) and Bushfire and Natural Hazards Cooperative Research Centre (CRC) projects and is involved in international wildfire research projects. These projects consider various aspects of extreme and dynamic bushfire propagation, the development of large conflagrations and bushfire risk management. His expertise is particularly relevant because of the large gap between the predictions of current mathematical models of fire behaviour and actual fire behaviour, and because of the increasing prevalence of extreme wildfires due to climate change.

Abstract: (shared lesson) In Australia, the majority of Wildland-Urban Interface (WUI) bushfire impacts are caused by ember storms, which are swarms of millimetre-scale embers flowing over terrain and roads, and that can easily breach control lines and impact properties. In the 2003 Canberra fires, 90% of all house losses were attributed to embers, but despite the strong evidence for the dominant contribution that embers make to property loss, faithful simulation of ember transport at the WUI remains difficult and elusive. Highly detailed computational fluid dynamics simulations are an established technique for understanding lofted embers from wildfires, however, these simulations do not include the transport of embers along the ground nor the entrainment of embers from the ground. Simulation techniques for near surface particle transport have been developed for other applications, and so this work considers extension of these efforts to a wildfire context. With a focus on regions in southeast Australia, we will outline some of the main challenges in understanding WUI fire impacts and describe progress towards simulating the behaviour of near surface particle transport in an idealised WUI. The overarching aim of this research is to develop simple prognostic models of when ember storms may occur and to develop reduced models of ember accumulation within a WUI region. These results will inform future planning decisions andember risk mitigation strategies that are balanced with other requirements relating to the liveability of the area.

Short bio: Duncan Sutherland is a Lecturer in the School of Science at UNSW Canberra, primarily researching the application of computational fluid dynamics techniques to simulate wildfire processes. They completed their PhD in Applied Mathematics at the University of Sydney in 2014, before taking a postdoctoral fellowship in wildfire spread simulation at Victoria University Melbourne.In 2022 they were awarded funding from the Australian Government and the government of the Australian Capital Territory to develop large-eddy simulation techniques for embers, which capture the entrainment, saltation and rebound of embers as observed in WUI fire events.

Abstract: (shared lesson) In Australia, the majority of Wildland-Urban Interface (WUI) bushfire impacts are caused by ember storms, which are swarms of millimetre-scale embers flowing over terrain and roads, and that can easily breach control lines and impact properties. In the 2003 Canberra fires, 90% of all house losses were attributed to embers, but despite the strong evidence for the dominant contribution that embers make to property loss, faithful simulation of ember transport at the WUI remains difficult and elusive. Highly detailed computational fluid dynamics simulations are an established technique for understanding lofted embers from wildfires, however, these simulations do not include the transport of embers along the ground nor the entrainment of embers from the ground. Simulation techniques for near surface particle transport have been developed for other applications, and so this work considers extension of these efforts to a wildfire context. With a focus on regions in southeast Australia, we will outline some of the main challenges in understanding WUI fire impacts and describe progress towards simulating the behaviour of near surface particle transport in an idealised WUI. The overarching aim of this research is to develop simple prognostic models of when ember storms may occur and to develop reduced models of ember accumulation within a WUI region. These results will inform future planning decisions andember risk mitigation strategies that are balanced with other requirements relating to the liveability of the area.

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