NOAA: National Oceanic and Atmospheric Administration
Storm Surge and Coastal Inundation
Venice, LA, still with at least two to three feet of water two weeks after Hurricane Katrina's storm surge - 2005Damage to manufactured and mobile homes at Surfside Beach, SC, after Hurricane Hugo's storm surge - 1989Hard Rock Casino barge (Biloxi, MS) completely destroyed during Hurricane Katrina - 2005Treasure Bay Casino (Biloxi, MS) was moved completely off its moorings by the storm surge from Hurricane Katrina - 2005Damage caused by the Galveston Hurricane and storm surge: the greatest natural disaster in terms of loss of life in U.S. history (6,000 to 8,000 individuals died in this event) - 1900House in North Carolina damaged by 15-foot storm surge that came with Hurricane Floyd - 1999Damage to beach front homes on Dauphin Island, AL, due to storm surge from Hurricane Katrina - 2005Storm surge from Hurricane Carol lashes Rhode Island Yacht Club - 1969


Storm Surge

Preparing coastal communities for storm surge flooding

Research and Development

NOAA is working on research and development projects to study coastal inundation processes and improve the calculation and communication of flooding risks. These efforts can help NOAA understand how to better predict storm surge and how to warn people in harm’s way.

Work on storm surge requires the coordination of a wide range of scientists from across NOAA’s offices. Therefore, in 2009 NOAA established the Storm Surge Roadmap in order to bring together its team of experts to work on the top priorities for the storm surge program. The Roadmap is a comprehensive NOAA strategy to holistically address its needs and work with the scientific community on a response. The Storm Surge Roadmap enables NOAA’s experts to work together on its biggest challenges, and to collaborate with other federal agencies and researchers to improve the science and technology within its program. It brings together meteorologists, oceanographers, engineers, computer scientists, social scientists, and many other experts to collaborate on improvements to NOAA’s storm surge capabilities.

Three goals define the Roadmap’s priorities:

  1. Accurately assess and predict storm surge water levels, reflecting the total water level during the event (caused by surge, tides, waves, rivers, and other oceanographic effects). This includes accounting for uncertainty in models and observations, and predicting it via ensembles and probabilistic forecasts.
  2. Intuitively describe inundation as flooding above ground level, addressing datum confusion in statements and maps.
  3. Communicate actionable information as guided by social science.

The Roadmap lays out a three-phase plan, which extends out over the next decade. The first three-year phase focuses on enhancements to the current system and lays the groundwork for bigger changes. The second phase focuses on intense research and development of a next generation of models and products. The final phase will transition these new tools into operations. Some of the Roadmap efforts underway are described below.

R & D in the social sciences

Expanding public communications

NOAA is using social science to improve communication of storm surge risks. Social science experts are consulting with emergency managers, the media, and the public to determine how much they know and how much information they need about storm surge hazards. These studies are informing the designs of NOAA products so that information is communicated clearly and quickly. The bottom line is to ensure that everyone understands the threat from a major storm surge event, and knows how to protect life and property.

For example, NOAA is working with researchers to assess how well the public understands storm surge risks. By conducting interviews and surveys with emergency managers in coastal areas, researchers have found that a significant portion of the surge-vulnerable population does not understand what storm surge is (including its causes and how it works), what their vulnerability is, and what the potential impacts are. People also desire more information from NOAA’s storm surge experts; surge has traditionally been included as a small part of description of all of a hurricane’s hazards. Additionally, social scientists are surveying broadcast meteorologists so that NOAA can understand what their perspectives are about the need for additional storm surge information for TV forecasts.

Since the results of these social science studies has illustrated the desire for additional information from NOAA on predicted storm surge, a team of experts has been developing and testing new potential surge-specific products. Experimental product prototypes are being presented to emergency managers, broadcast meteorologists, and the public for thorough evaluation before eventual implementation. This prototyping process is enabling NOAA to assess how it can best communicate storm surge information in a way that promotes appropriate action in vulnerable areas.

R & D in storm surge modeling

Improving coastal inundation modeling

The total water level that occurs during a storm surge event is caused by the winds and pressure of a storm, but also by the tides, waves, and rivers. NOAA’s modeling experts are improving the prediction of a storm’s total water level by coupling storm surge, tide, wave, and river models. These complex model components simulate different processes that drive water levels in these environments, and by getting them to talk to each other, NOAA can improve storm surge forecasts in coasts and estuaries. For example, tides are being added to NOAA’s operational storm surge model SLOSH . This advancement will benefit storm surge predictions for both tropical and extratropical storms.

NOAA has also recently developed an extratropical storm surge model that includes the effects of tides (ESTOFS). This model will next be coupled with wave models to include their contributions to coastal flooding, and is also being used by NOAA’s river modelers so that storm surge conditions can be predicted as they travel up a river.

There are numerous computational models of weather and oceans, each with different strengths and weaknesses. Since we know that a prediction that combines outputs from several different models delivers better results, NOAA is testing a system that provides an ensemble of storm surge predictions using multiple hurricane and storm surge models. This set of results can inform forecasters about a range of forecast scenarios and provide information about uncertainty in the predictions. Decision makers can use this data to improve preparations in the face of an event.

Combining coastal and inland flooding processes

CI-FLOW is a project in North Carolina that combines a high resolution surge and wave model with a hydrologic model of river flow. CI-FLOW is determining how these different types of models can pass information about water levels back and forth, and how these models can improve predictions. Ensembles of river predictions are created and intelligently processed in order to best predict a river’s impact on coastal storm surge flooding. This type of work is guiding the next generation of storm surge modeling capabilities at NOAA.

This video describes the CI-FLOW project.

R & D for nearshore wave prediction

Nearshore Wave Prediction System

The Nearshore Wave Prediction System is a real-time deterministic modeling system, focused on extra-tropical events. The system extends the global WAVEWATCH III® wave model to resolutions of less than 1 km, which is required to resolve the relevant nearshore processes.

Weather forecast offices will run this system locally. They will use forecaster-developed local wind fields, and water level and current fields from the Real Time Ocean Forecast System and the Extratropical Surge and Tide Operational Forecast System (ESTOFS).

NOAA is coupling nearshore wave and circulation models within this system. The physical processes that will be modeled include the effect of currents on waves (Doppler shifting, current refraction, and shoaling), as well as the influence of the waves on the surge and inundation through radiation stresses.