Dynamic vulnerability factors for impact-based flash flood prediction

Social vulnerability explains the sociological and human-dependent circumstances that translate a natural event into a deadly disaster. But, what are the space-time characteristics of vulnerability (i.e., dynamic vulnerability) that influence how people are impacted by a specific natural hazard? This paper performs a critical analysis of previous flood-related human impact and vulnerability studies to better understand and summarize the human-related factors that determine the impacts from flash flood events. The paper is motivated by the hypothesis that the intersection of the spatiotemporal context of the hazard with the distribution of people and their characteristics across space and time reveals different paths of vulnerability and defines the most probable space of an exposed area in terms of deadly impacts. Based on this idea, a conceptual model for assessing vulnerability to flash flooding is developed and presented herein. The most important advance of the current research in comparison with previous efforts in vulnerability assessment is the introduction of the concept of the spatial and temporal variability of vulnerability. This means that the proposed conceptual model does not consider vulnerability as a static synopsis that can be described by a single map, but as an ever-evolving process derived from the interaction of social and physical dynamics. The dynamic perspective of vulnerability is key for the identification of pertinent vulnerability variables to be used for flash flood vulnerability assessment and dynamic mapping, and prediction.