Uncertainty in Predicted Tropical Cyclone Path and Landfall Characteristics for Landfalling Storms to Support External Hazard Probabilistic Risk Assessments for Critical Infrastructure-A Preliminary Analysis

Critical infrastructure facilities, such as nuclear power plants, are often located in coastal regions exposed to tropical cyclones (TCs). These facilities may employ permanent protective measures as well as strategies that require manual (human) actions to install temporary features (e.g., flood protection berms and pumps). In addition to the possibility of hardware failures, there is a possibility that actions will be unsuccessful due to delayed organizational decision-making, human errors, and differences between predicted and experienced hazard characteristics. Accurate external hazard probabilistic risk assessments (XHPRAs) must quantify these error probabilities, which depend on factors such as the information available to support decisions, the time available to perform actions, and the environmental conditions under which actions are performed. These factors are subject to uncertainty due to uncertainty in TC forecasts. To support XHPRAs for critical infrastructure facilities, this paper seeks to explore uncertainty in the conditions under which human actions will be performed, with particular emphasis on the time available to execute actions. We analyzed National Oceanic and Atmospheric Administration (NOAA) geographic information system (GIS) datasets related to advisory forecast TC track data for 2012-2020. For each historic storm, we compared advisory forecasted track data (e.g., predicted landfall locations, times, and wind speed) to the observed track to understand errors and uncertainty.