An Integrated Scenario Ensemble-Based Framework for Hurricane Evacuation Modeling: Part 2-Hazard Modeling.

Area of Science:

• Atmospheric Science
• Hydrology
• Coastal Engineering

Background:

• Hurricane track and intensity prediction uncertainty leads to suboptimal decisions like unnecessary evacuations.
• Accurate hazard assessment is critical for effective evacuation planning and risk management.

Purpose of the Study:

• To develop and demonstrate a physics-based hazard modeling approach that accounts for hurricane evolution uncertainty.
• To provide probabilistic water inundation and wind speed levels for risk-based evacuation modeling.

Main Methods:

• A loosely coupled model system combining Weather Research and Forecasting (WRF), Coupled Routing and Excess STorage (CREST), and ADvanced CIRCulation (ADCIRC) models.
• An ensemble method using perturbations in WRF's initial/boundary conditions and model physics to generate multiple storm scenarios.
• Driving coupled hydrologic and hydrodynamic models with the ensemble of hurricane predictions to compute inundation and wind speeds.

Main Results:

• The ensemble-based approach captures hurricane evolution uncertainty, providing a range of "best-case" to "worst-case" scenarios.
• Inundation, river runoff, and wind hazard predictions are sensitive to the accuracy of mesoscale meteorological simulations.
• The ensemble envelope successfully brackets observed hurricane behavior, as demonstrated with Hurricane Isabel (2003).

Conclusions:

• The developed physics-based, ensemble modeling framework enhances hurricane hazard prediction by quantifying uncertainty.
• This probabilistic approach supports a more robust, risk-based evacuation strategy, moving beyond traditional deterministic methods.
• Improved accuracy in meteorological simulations, especially with shorter lead times, enhances the reliability of hazard predictions.