Article

Modeling and mapping dynamic vulnerability to better assess WUI evacuation performance

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Abstract

Wildland‐urban interface (WUI) fire incidents are likely to become more severe and will affect more and more people. Given their scale and complexity, WUI incidents require a multidomain approach to assess their impact and the effectiveness of any mitigation efforts. The authors recently produced a specification for a simulation framework that quantifies evacuation performance during WUI incidents including inputs from three core domains: fire development, pedestrian performance and vehicular traffic [26]. This framework could produce new insights by simulating evolving conditions of WUI incidents based on developments and interactions between the core components. Thus, it aims to overcome known limitations of previous approaches (eg, static assessment, single domain approaches, or lack of projection), as well as to provide explanatory insights into the outcomes produced by the simulation. The proposed framework would also advance geo‐spatial mapping of WUI incidents. The concept of dynamic vulnerability, , is at the core of the framework and is enabled by the integrated simulation framework and the emergent conditions predicted. This allows users to construct richer incident narratives from the perspective of specific locations or subpopulations, and also makes fewer simplifying assumptions regarding interactions between the three core domains.

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... The consequences of wildland-urban fire disasters in WUI communities become even more exacerbated considering the often limited social, financial, and institutional capacities of WUI communities to prepare for, respond to, cope with, and recover from disasters. Also, socially vulnerable populations in WUI communities typically experience greater impacts from disasters (e.g., Davies et al. 2018;Gwynne et al. 2019;McDaniel et al. 2021;Thomas et al. 2009)). ...
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Destruction of human-built structures occurs in the ‘wildland–urban interface’ (WUI) – where homes or other burnable community structures meet with or are interspersed within wildland fuels. To mitigate WUI fires, basic information such as the location of interface areas is required, but such information is not available in Canada. Therefore, in this study, we produced the first national map of WUI in Canada. We also extended the WUI concept to address potentially vulnerable industrial structures and infrastructure that are not traditionally part of the WUI, resulting in two additional maps: a ‘wildland–industrial interface’ map (i.e. the interface of wildland fuels and industrial structures, denoted here as WUI-Ind) and a ‘wildland–infrastructure interface’ map (i.e. the interface of wildland fuels and infrastructure such as roads and railways, WUI-Inf). All three interface types (WUI, WUI-Ind, WUI-Inf) were defined as areas of wildland fuels within a variable-width buffer (maximum distance: 2400 m) from potentially vulnerable structures or infrastructure. Canada has 32.3 million ha of WUI (3.8% of total national land area), 10.5 million ha of WUI-Ind (1.2%) and 109.8 million ha of WUI-Inf (13.0%). The maps produced here provide a baseline for future research and have a wide variety of practical applications. ********************************** Full text available open access: http://www.publish.csiro.au/wf/WF16221
Article
Forest fires are an annual occurrence in many parts of the world forcing large-scale evacuation. The frequent and growing occurrence of these events makes it necessary to develop appropriate evacuation plans for areas that are susceptible to forest fires. The buildingEXODUS evacuation model has been extended to model large-scale urban evacuations by including the road network and open spaces (e.g. parks, green spaces and town squares) along with buildings. The evacuation simulation results have been coupled with the results of a forest fire spread model and applied to the Swinley forest fire which occurred in Berkshire, UK in May 2011. Four evacuation procedures differing in the routes taken by the pedestrians were evaluated providing key evacuation statistics such as time to reach the assembly location, the distance travelled, congestion experienced by the agents and the safety margins associated with using each evacuation route. A key finding of this work is the importance of formulating evacuation procedures that identifies the threatened population, provides timely evacuation notice, identifies appropriate routes that maintains a safe distance from the hazard front thereby maximising safety margins even at the cost of taking longer evacuation routes. Evacuation simulation offers a means of achieving these goals.
Conference Paper
This paper addresses the need for new measures and models of infrastructure performance that can facilitate the strengthening of community resilience to disasters. While many infrastructure measures and models focus on performance in terms of disaster-induced damage, from the perspective of populations and cities that would be affected, there is a need for analysis of service loss and of approaches to rapidly restore service in an emergency. Focusing on transportation, this paper notes limitations of current performance measures, proposes a systems analytic framework that addresses community resilience, and demonstrates how the framework can be applied to analyze and model transportation disruption in earthquakes and other disasters. The approach is demonstrated for a case study of south coastal British Columbia, Canada, with particular attention to the role of maritime transportation in the distribution of one essential commodity, gasoline fuel. Coastal communities in this region are extremely reliant on maritime transportation for delivery of essential goods such as fuel, and because of the shift towards just-in-time production systems, have very little storage or warehousing capacity. Expert interviews, stakeholder workshops, satellite-based tracking of ships, and network analyses are used to characterize the transportation system and assess risk and resilience. Two approaches to system analysis are implemented: one emphasizing network topology, and the other focusing on network functionality. This enables a comparison of the strengths and limitations of these two major methodological approaches. In the case study demonstration, the topological approach is able to capture, with relatively low data requirements, the relative vulnerability of communities situated in different parts of the network. Resilience-enhancing strategies that are related to network topology, such as adding network links as a response in emergencies, can be readily assessed. The topological approach is limited, however, in its ability to address detailed damage and operational issues related to emergency response actions that are key to resilience analysis. In the second approach, a functional model is developed that emphasizes flows in the network. This enables a more realistic representation of system operations, thereby facilitating more specific understanding of how transportation damage can lead to disruption of fuel flows and impacts to communities. The functional model can be readily integrated with hazard and facility damage models. The approach is particularly advantageous in being able to capture time-dependent variables such as reserve volumes and supply deliveries, which are crucial types of information for assessing how different decision options (e.g., seismic retrofit of port facilities, increasing storage capacity, adding shipping routes) could enhance community resilience. Data requirements are very high, however, and pose an important limitation to this approach.
Book
Revised and significantly expanded, the fifth edition of this classic work offers both new and substantially updated information. As the definitive reference on fire protection engineering, this book provides thorough treatment of the current best practices in fire protection engineering and performance-based fire safety. Over 130 eminent fire engineers andresearchers contributed chapters to the book, representing universities and professional organizations around the world. It remains the indispensible source for reliable coverage of fire safety engineering fundamentals, fire dynamics, hazard calculations, fire risk analysis, modeling and more. With seventeen new chapters and over 1,800 figures, the this new editioncontains: • Step-by-step equations that explain engineering calculations • Comprehensive revision of the coverage of human behavior in fire, including several new chapters on egress system design, occupant evacuation scenarios, combustion toxicity and data for human behavior analysis • Revised fundamental chapters for a stronger sense of context • Added chapters on fire protection system selection and design, including selection of fire safety systems, system activation and controls and CO2 extinguishing systems • Recent advances in fire resistance design • Addition of new chapters on industrial fire protection, including vapor clouds, effects of thermal radiation on people, BLEVEs, dust explosions and gas and vapor explosions • New chapters on fire load density, curtain walls, wildland fires and vehicle tunnels • Essential reference appendices on conversion factors, thermophysical property data, fuel properties and combustion data, configuration factors and piping properties.
Article
Evacuation is a time critical process in which the highest priority is to get those people who may be affected by a disaster out of the danger zone as fast as possible. For disaster-prone areas, authorities often distribute evacuation plans well in advance, or encourage the population to prepare themselves for eventual disasters. This paper presents an approach to such planning ahead for evacuation that tightly couples optimization and traffic simulation in order to determine optimal evacuation time and exit from the area for each evacuee. In this paper, we discuss the approach's properties and illustrate its performance using two case studies of wildfire-prone areas in the state of Victoria, Australia. The results show that our approach can lead to significant improvements when compared to ad-hoc evacuation, but these improvements also strongly depend on population density and road network topology. More generally, our research highlights the significant benefits of tightly coupling optimization and simulation for evacuation modeling.
Article
While the wildland-urban interface (WUI) is not a new concept, fires in WUI communities have rapidly expanded in frequency and severity over the past few decades. The number of structures lost per year has increased significantly, due in part to increased development in rural areas, fuel management policies, and climate change, all of which are projected to increase in the future. This two-part review presents an overview of research on the pathways for fire spread in the WUI. Recent involvement of the fire science community in WUI fire research has led to some great advances in knowledge; however, much work is left to be done. While the general pathways for fire spread in the WUI (radiative, flame, and ember exposure) are known, the exposure conditions generated by surrounding wildland fuels, nearby structures or other system-wide factors, and the subsequent response of WUI structures and communities are not well known or well understood. This first part of the review covers the current state of the WUI and existing knowledge on exposure conditions. Recommendations for future research and development are also presented for each part of the review.
Article
This statistical meta-analysis (SMA) examined 38 studies involving actual responses to hurricane warnings and 11 studies involving expected responses to hypothetical hurricane scenarios conducted since 1991. The results indicate official warnings, mobile home residence, risk area residence, observations of environmental (storm conditions) and social (other people's behavior) cues, and expectations of severe personal impacts, all have consistently significant effects on household evacuation. Other variables—especially demographic variables—have weaker effects on evacuation, perhaps via indirect effects. Finally, the SMA also indicates that the effect sizes from actual hurricane evacuation studies are similar to those from studies of hypothetical hurricane scenarios for 10 of 17 variables that were examined. These results can be used to guide the design of hurricane evacuation transportation analyses and emergency managers' warning programs. They also suggest that laboratory and Internet experiments could be used to examine people's cognitive processing of different types of hurricane warning messages.
Chapter
This chapter provides a broad overview of the ecological and social aspects of wildfires, their impacts, and management in Canada. We describe the Canadian fire landscape, including vegetation and fire ecology, with an emphasis on the boreal forest. Wildfire causes and their impacts from past to recent events in 2003 and 2011, and communities at current and future risk of wildfires are described. Wildfire management, including land use, institutions involved in wildfire management, and policies and practices are explained. Wildfire mitigation as practiced by governments and homeowners, community response to wildfire, and relief and recovery following a wildfire are discussed.
Article
In recent years, advances in computational power and spatial data analysis (GIS, remote sensing, etc) have led to an increase in attempts to model the spread and behvaiour of wildland fires across the landscape. This series of review papers endeavours to critically and comprehensively review all types of surface fire spread models developed since 1990. This paper reviews models of a simulation or mathematical analogue nature. Most simulation models are implementations of existing empirical or quasi-empirical models and their primary function is to convert these generally one dimensional models to two dimensions and then propagate a fire perimeter across a modelled landscape. Mathematical analogue models are those that are based on some mathematical conceit (rather than a physical representation of fire spread) that coincidentally simulates the spread of fire. Other papers in the series review models of an physical or quasi-physical nature and empirical or quasi-empirical nature. Many models are extensions or refinements of models developed before 1990. Where this is the case, these models are also discussed but much less comprehensively. Comment: 20 pages + 9 pages references + 1 page figures. Submitted to the International Journal of Wildland Fire
Article
In recent years, advances in computational power and spatial data analysis (GIS, remote sensing, etc) have led to an increase in attempts to model the spread and behaviour of wildland fires across the landscape. This series of review papers endeavours to critically and comprehensively review all types of surface fire spread models developed since 1990. This paper reviews models of an empirical or quasi-empirical nature. These models are based solely on the statistical analysis of experimentally obtained data with or without some physical framework for the basis of the relations. Other papers in the series review models of a physical or quasi-physical nature, and mathematical analogues and simulation models. The main relations of empirical models are that of wind speed and fuel moisture content with rate of forward spread. Comparisons are made of the different functional relationships selected by various authors for these variables. Comment: 22 pages + 7 pages references + 2 pages tables + 2 pages figures. Submitted to International Journal of Wildland Fire
Article
A workshop, known as “Operation Tomodachi—Fire Research” was held in Tokyo, Japan from July 1 to July 4, 2012. Tomodachi means friendship in Japanese. This workshop, under the direction of Dr. Samuel L. Manzello of EL-NIST and Dr. Tokiyoshi Yamada of the University of Tokyo, was conducted in partnership with the Japan Association of Fire Science and Engineering (JAFSE). The objective was to: (1) develop scientific knowledge and translate it to building codes and standards that will be of use to both countries to reduce the devastation caused by unwanted fires, (2) provide a forum for next generation researchers to present their work in order to develop new research collaborations, (3) and allow USA participants a chance to visit excellent large-scale research facilities available in Japan that are of use to the research topics of this workshop. This is a formal continuation of the kickoff meeting held at NIST's Engineering Laboratory (EL-NIST) in June 2011. USA presentations were delivered from: NIST, Purdue University, University of Texas-Austin, Michigan State University, University of Michigan, Insurance Institute for Business and Home Safety (IBHS), Worcester Polytechnic Institute (WPI), University of California-Berkeley, California Polytechnic University (CALPOLY), Underwriters Laboratories (UL), and the University of Delaware (organizations are listed based on the order of oral presentation). Japanese presentations were delivered from: The University of Tokyo, Building Research Institute (BRI), Takenaka Corporation, Center for Better Living, Shimizu Corporation, Tokyo University of Science (TUS), National Institute for Land and Infrastructure Management (NILIM), Kyoto University, National Research Institute of Fire and Disaster (NRIFD), Yamagata University, and Kobe University (organizations are listed based on the order of oral presentation). All of the presentations are documented in a recent NIST Special Publication (NIST SP 1137). The present paper provides a detailed summary for the need of this workshop as well as the findings obtained from the event. It is desired that this activity will motivate the next generation of researchers to explore and develop research collaborations related to emerging areas of fire safety science. The authors are hopeful that new and exciting activities specific to other countries may come out of this type of event.
Article
Regional evacuation modeling is treated as a five step process: involving vehicle trip generation, trip departure time, trip destination, and trip route selection modeling, supplemented by plan set-up and analysis procedures. Progress under each of these headings is reviewed and gaps in the process identified. The potential for emergency planners to make use of real time traffic data, resulting from the recent technical and economic revolutions in telecommunications and infrared traffic sensing, is identified as the single greatest opportunity for the near future; and some beginnings in the development of real time dynamic traffic modeling specifically geared to evacuation planning are highlighted. Significant data problems associated with the time of day location of large urban populations represent a second area requiring extensive research. A third area requiring much additional effort is the translation of the considerable knowledge we have on evacuee behavior in times of crisis into reliable quantitative measures of the timing of evacuee mobilization, notably by distance from the source of the hazard. Specific evacuation models are referenced and categorized by method. Incorporation of evacuation model findings into the definition of emergency planning zone boundaries is also discussed. 90 refs., 8 figs., 1 tab.
Article
This project was motivated by recent research that has advocated the need for a better understanding of and planning for evacuations of residential subdivisions under threat from wildfires. Prior work has suggested that the density of housing units and ineffective evacuation routing and egress may have contributed to fatalities in subdivisions in which residents were unable to evacuate when the need arose. To evaluate the effects of development density and street network layout, this study utilized simulation to represent and evaluate various evacuation scenarios at the neighborhood level under ranges of housing density and threat urgency. The results of this study illustrate the relationships between the traffic that can be accommodated by a roadway network; the location and number of egress points; and the time during which vehicles enter and exit the network. Most significantly, it showed how changes in traffic volume need to be accompanied by corresponding increases or decreases in time and/or egress capacity to move evacuees out of the threat zone. Similarly, changes in the network (i.e., adding and/or modifying the location of exits) were also shown to significantly decrease evacuation clearance times and increase the total exiting traffic.