NGI Conducts Sensitivity Studies on Hurricane Katrina's Storm Surge

In collaboration with the NOAA Hurricane Research Division and the NOAA National Weather Service Meteorological Development Laboratory, the Northern Gulf Institute (NGI) is performing sensitivity tests using hydrodynamic models to understand the factors that contributed to Hurricane Katrina’s historic storm surge in August 2005. Katrina’s surge is unprecedented in the U.S. for its elevation, area coverage, and levee breaches in New Orleans. NGI researchers are using storm surge models such as ADCIRC (ADvanced CIRCulation) and SLOSH (Sea, Lake and Overland Surges from Hurricanes) to simulate Katrina’s inundation in coastal Mississippi and Louisiana to address the fundamental physics of storm surge, the impact of levee configurations, and the loss of wetlands resulting from hurricane events.

Background: Storm surge prediction and research has been identified as a deficient area requiring immediate and significant improvements. Specifically, the NOAA document Interagency Strategic Research Plan for Tropical Cyclones: The Way Ahead states it is a top-five priority and an important component of NOAA’s future hurricane prediction system in which ADCIRC will be coupled with NOAA’s Hurricane Weather Research and Forecasting model. Storm surge research has also been identified as a high priority action item in the National Science Foundation document Hurricane Warning: The Critical Need for a National Hurricane Research Initiative.

Significance: First, this research provides an improved understanding of hurricane wind structure on the storm surge so that emergency preparedness officials can better anticipate widespread storm surge events. Secondly, it quantifies the impact of the Louisiana wetlands and levee system on storm surges. For example, simulations with SLOSH show that the Mississippi River levees impeded the surge from spreading westward into Barataria Bay, accumulating the water in areas east of the levee system as the storm moved northward. This resulted in faster inundation in Chalmette and the Ninth Ward by 1-5 hours, and a higher surge of 3-7 feet. In contrast, SLOSH shows the levees had little impact on the timing or height of the storm surge on the Mississippi coast. This research supports NOAA’s Mission Goal 3 - Serve Society's Needs for Weather and Water Information.