An Integrated Scenario Ensemble‐Based Framework for Hurricane Evacuation Modeling: Part 2—Hazard Modeling

Abstract

Hurricane track and intensity can change rapidly in unexpected ways, thus making predictions of hurricanes and related hazards uncertain. This inherent uncertainty often translates into suboptimal decision-making outcomes, such as unnecessary evacuation. Representing this uncertainty is thus critical in evacuation planning and related activities. We describe a physics-based hazard modeling approach that (1) dynamically accounts for the physical interactions among hazard components and (2) captures hurricane evolution uncertainty using an ensemble method. This loosely coupled model system provides a framework for probabilistic water inundation and wind speed levels for a new, risk-based approach to evacuation modeling, described in a companion article in this issue. It combines the Weather Research and Forecasting (WRF) meteorological model, the Coupled Routing and Excess STorage (CREST) hydrologic model, and the ADvanced CIRCulation (ADCIRC) storm surge, tide, and wind-wave model to compute inundation levels and wind speeds for an ensemble of hurricane predictions. Perturbations to WRF's initial and boundary conditions and different model physics/parameterizations generate an ensemble of storm solutions, which are then used to drive the coupled hydrologic + hydrodynamic models. Hurricane Isabel (2003) is used as a case study to illustrate the ensemble-based approach. The inundation, river runoff, and wind hazard results are strongly dependent on the accuracy of the mesoscale meteorological simulations, which improves with decreasing lead time to hurricane landfall. The ensemble envelope brackets the observed behavior while providing "best-case" and "worst-case" scenarios for the subsequent risk-based evacuation model.

Steps towards Modeling Community Resilience under Climate Change: Hazard Model Development

“…The Advanced Circulation (ADCIRC [50]) model serves as the hydrodynamic model in the STORM-CoRe coupled model system. ADCIRC, which has been in use for over 35 years, has seen a wide variety of applications, which include flood inundation maps for coastal areas [51,52], modeling baroclinic driven circulation [53], real-time prediction of storm surge to provide guidance [13,21], surge and riverine flooding [14,[54][55][56], modeling tides and wind driven circulation [57,58] and an integrated, scenario-based evacuation and sheltering system [56,59]. The ADCIRC model employs the shallow water equations in their non-linear formulation, subject to hydrostatic and Boussinesq approximations.…”

An Integrated Scenario Ensemble‐Based Framework for Hurricane Evacuation Modeling: Part 1—Decision Support System

“…We briefly summarize it here, with a particular focus on the issues most relevant to this study. The hazard-related literature is addressed in the companion paper, (4) which focuses on the hazard portion of the new framework. Sections 2.1 and 2.2 review engineering decision support models and behavioral studies, respectively, in each case highlighting the ways the new framework uses and extends the literature.…”

“…Steps 1 to 4 form a coupled physics-based hazard assessment framework that is described more fully in the companion paper. (4) The approach for the hazard modeling is to use existing state-of-the-art models with proven performance and prediction skill to compute the inundation and wind hazard.…”

“…In the ISE framework, an ensemble of probabilistic scenarios describes the probable evolution of a hurricane, as detailed in the companion paper by Blanton et al (4) For each hurricane scenario, we compute inundation level and wind speed maps at each time step. The framework also captures the dynamic decision-making and movement of the population during the event.…”

“…This paper focuses on the overall computational framework and how all the components fit together. Other papers describe the individual components in more detail as follows-hazards modeling in Blanton et al (4) , scenario tree development method in Yang et al (5) , MSP formulation and solution algorithm in Yi et al (6) , and dynamic traffic assignment model within the MSP in Li et al (7) Following a summary of the literature in Section 2, the new approach is compared to existing practice in Section 3, and the ISE framework is presented in Section 4. In Section 5, we present a fullscale case study application to illustrate the required inputs, step-by-step process, output, and benefit over existing approaches.…”