Following the general terminology of natural hazards, wildfire risk assessment should include all factors that affect both the likelihood of occurrence and the potential damages (including exposure and vulnerability) that the fire may cause, not only on human lives and assets, but also on ecosystem services and ecological values. Historically, wildfire risk literature developed a particular set of concepts and terms, sometimes independent from the general literature on natural or technological hazards [1]. FAO terminology[2], for instance, defined in 1986 Fire Danger as “the resultant, often expressed as an index, of both constant and variable factors affecting the inception, spread, and difficulty of control of fires and the damage they cause”, while fire hazard was related to fuel conditions and fire risk was related to causative agents. Growing acceptance of the UN natural hazards terminology by the fire community implies that those terms are nowadays mostly discontinued, although reminiscences are still found in historical risk assessment systems. In any case, most fire managers now consider that integrated wildfire risk assessment should consider both the factors affecting fire ignition and propagation (e.g., fire causes, fuel properties, terrain and weather conditions), as well as the evaluation of assets at stake, those that may be affected by direct or indirect impacts of fires (human health and lives, houses, infrastructures, ecosystem services and ecological values).
Following common terminology of natural hazards, wildfire risk assessment has been approached in FirEUrisk from an holistic view, including the main three components: hazard, exposure and vulnerability [3] [4]. As a general introduction to Figure 1, which includes the integration scheme used in the project, these three components have been identified as follows:
- Danger (or Hazard) defined as the probability that a fire starts or propagates in a certain area and point in time;
- Exposure, which represents the people and assets that may suffer damage from wildfires;
- Vulnerability, which estimates the potential damages caused by the fire.
Figure 1 includes the different variables that each of the three components entail:
Figure 1. Conceptual integration of wildfire risk assessment components within the FirEUrisk project (after [5]).
In summary, wildfire risk assessment entails an estimation of when, where, why and how wildfires are more likely to occur and propagate, which areas are potentially exposed and what potential damages those fires may imply. Therefore, a comprehensive risk characterisation should include these three dimensions of risk (danger, exposure, and vulnerability). Ideally, the risk assessment system should also be comprehensive (all relevant variables considered), flexible (applicable to a wide range of spatial and temporal conditions), coherent (internally logical) and replicable (based on transparent methods). The constituents of such a system can be grouped in two categories: on one hand, components which identify the different dimensions of wildfire risk that the system is considering (for instance, ignition source/causes, propagation potential or landscape resilience), and on the other hand, variables which indicate specific parameters. These variables can be further divided into first-order quantities (those directly measurable, such as wind speed or population density) and second order (those estimated from a combination of first order variables, such as fire rate of spread). The aggregation of variables (either of first or second order) into different dimensions of risk will lead to generating risk components. For instance, human ignition is a component that requires different input variables related to how humans may generate fires, either intentionally or by carelessness.
Click here for the Interactive FirEUrisk Conceptual Framework Diagram
¶ References
Bachmann, A., & Allgöwer, B. (2001). A consistent wildland fire risk terminology is needed! Fire Management Today, 61, 28-33. ↩︎
FAO (1986). Wildland fire management terminology. Terminologie de la lutte contre les incendies de forêt. Terminología del control de incendios en tierras incultas. In. Rome: Food and Agriculture Organization, Forestry Paper. ↩︎
Tagarev, T., & Papadopoulos, G.A. (2020). Integrating the risk management cycle. In A. Casajus Valles, M. Marin Ferrer, & K. Poljanšek, Clark, I. (Eds.), Science for Disaster Risk Management 2020: acting today, protecting tomorrow (pp. 49-106). Luxembourg: UR 30183 EN, Publications Office of the European Union. ↩︎
UNISDR (2009). Terminology on Disaster Risk Reduction. Geneva, Switzerland: United Nations International Strategy for Disaster Reduction (UNISDR), http://www.unisdr.org/files/7817_UNISDRTerminologyEnglish.pdf. ↩︎
Chuvieco, E., Yebra, M., Martino, S., Thonicke, K., Gómez-Giménez, M., San-Miguel, J., Oom, D., Ramona Velea, Florent Mouillot, Juan R. Molina, Ana I. Miranda, Diogo Lopes, Michele Salis, Marin Bugaric, Mikhail Sofiev, Evgeny Kadantsev, Ioannis Gitas, Dimitris Stavrakoudis, George Eftychidis, Bar-Massada, A., Alex Neidermeier, Valerio Pampanoni, Pettinari, M.L., Arrogante, F., Ochoa, C., Moreira, B., & Viegas, D. (2023). Towards an integrated approach to wildfire risk assessment: when, where, what and how may the landscapes burn. Fire, 6, 215, doi210.3390/fire6050215. ↩︎