Options for real-time forecasting of storm tide inundation for emergency management in Queensland, Australia

Whilst evacuation arrangements for the large storm tide experienced during Tropical Cyclone (TC) Yasi in North Queensland, Australia, in 2011 were successful with no deaths from this hazard, post-event assessment of the current storm tide warning system suggested that improvements are possible. Workshopping with emergency managers identified the translation of storm tide warning levels into onshore estimates of inundation, refinement of the timing of the peak surge with regards to high tide and also understanding the underlying uncertainties currently unexpressed by the deterministic forecast as potential areas for development. Here, the potential for probabilistic real-time storm tide inundation forecasting is explored via an options analysis for each component of the storm tide forecasting process: TC tracks, wind fields, hydrodynamic modeling and post-processing of outputs for use in risk assessment. We identify the high degree of uncertainty in the forecast TC track as the key factor governing the development of a probabilistic system. This uncertainty requires simulation of a large ensemble, necessitating run-time optimization of the wind field and hydrodynamic modeling processes. Taking into account the results of the options analysis, we propose a feasible real-time storm tide forecasting system. A case study demonstrating this system based on TC Yasi (2011) is presented.