NOAA Research Finds East Coast is Hit by 25 Meteotsunamis Each Year

Brian Donegan
Published: April 16, 2019

The East Coast of the United States is hit by about 25 meteotsunamis each year, according to new research published this month by NOAA.

Meteotsunamis are a type of tsunami, but instead of being generated by an underwater earthquake, the source is meteorological, which gives them their unique name.

Thunderstorms are the instigator for the development of many meteotsunamis because they sometimes provide the spike in wind speed and the atmospheric pressure change needed to trigger their formation.

Most of the more-than-two-dozen meteotsunamis along the U.S. East Coast each year are less than 1.5 feet high and relatively harmless, NOAA said. In a typical year, only about one of those meteotsunamis exceeds 2 feet in height, which is large enough to cause injuries and destruction.

One example of a higher-end East Coast meteotsunami occurred June 13, 2013, generating a 6-foot wave that injured three people on a jetty in New Jersey during otherwise calm weather conditions. Caused by an intense thunderstorm-related wind burst known as a derecho as it moved offshore, the waves were detected by more than 16 NOAA tide gauges along the East Coast, according to NOAA.

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The NOAA researchers involved in this study analyzed 22 years (1996-2017) of water-level observations from 125 tide gauges along the East Coast and found evidence of 548 meteotsunamis over that time period, including one that occurred during Hurricane Irma in September 2017.

Each colored dot depicts the average number of meteotsunami events per year at that respective location.
(Source: NOAA)

NOAA determined that most East Coast meteotsunamis happen during the summer – particularly in July, when thunderstorms commonly form with the heating of the day – and in the winter due to coastal storms and nor'easters.

The Carolinas, northern Florida and the Long Island Sound have the highest occurrence of meteotsunamis, the research found. The largest waves occur in areas where estuaries or the coastline shape can enhance them.

Myrtle Beach, South Carolina, had the largest number of meteotsunami events over the 22 years studied. There were 148 meteotsunamis observed there, an average of 7.2 per year. In second place was Duck, North Carolina, where NOAA observed 130 events, an average of 6 meteotsunamis per year.

The highest averages per year at locations with at least five years of data were at Cape Hatteras and Wrightsville Beach in North Carolina, with 8.9 and 8.7 meteotsunami events per year.

Meteotsunamis are not exclusive to the U.S. East Coast; they occur around the world. For example, the Great Lakes average about 100 meteotsunami events per year – more than the East Coast. Most of these are small, but higher, destructive meteotsunamis happen on the Great Lakes about once per decade on average.

(MORE: Two Meteotsunamis Form on Lake Michigan in One Day

Scientists hope that with additional research a forecast and warning system for meteotsunamis can eventually be developed to protect those potentially in harm's way.

Croatian scientists are working on a warning system for meteotsunami events on the Adriatic Sea, and U.S. scientists hope to build off their progress.

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