Meteotsunamis in the Gulf of Mexico and Eastern United States During Hurricane Seasons 2016-2017

Tropical cyclones are one of the most destructive natural hazards. Flood-related damages represent a large portion of losses and casualties. Characterizing and predicting total water levels during extreme storms is important to increase the resilience of coastal communities.

Numerical simulation and prediction of coastal water levels during extreme storms is still challenging, despite the latest scientific and computational advances. Total water levels in the nearshore are usually computed as the superposition of the astronomic tide, storm surge, gravity wave setup, water level changes due to infragravity waves, wave runup, and swash motions. However, there is enough observational evidence of the existence of other types of water level oscillations, such as meteotsunamis, during tropical cyclones. Despite the potential hazard associated with these types of waves, the generation and propagation mechanisms of meteotsunamis during tropical cyclones remain elusive.

In this study, we analyze the meteotsunami events along the Gulf of Mexico and U.S. East coast during the hurricane seasons 2016 and 2017. This period includes hurricanes Maria (2017), Irma (2017), Harvey (2017), Matthew (2016), and Hermine (2016). For the duration of each hurricane, we analyzed the free surface elevation measurements from the National Oceanic and Atmospheric Administration (NOAA) tidal gauge network. We complemented the analysis with atmospheric radar reflectivity, sea level atmospheric pressure, wind speed and wind gust, and air temperature measurements (when available). Results indicate the presence of meteotsunamis with maximum water level anomalies of up to 0.8 m. In three of the five analyzed hurricanes maximum meteotsunami elevations were higher than 0.45 m. Most of these events were triggered by spiral rainbands. We used the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modelling system to identify which types of spiral rainbands have a higher potential to trigger meteotsunamis. We used atmosphere-ocean coupled idealized simulations to untangle the main generation and propagation mechanisms.