North Carolina

Mini-tsunamis keep hitting the East Coast, NOAA says. But what exactly are they?

Researchers looked at the frequency and height of meteotsunami waves over 22 years.
Researchers looked at the frequency and height of meteotsunami waves over 22 years. NOAA

A freak wave about 6 feet high crashed into a New Jersey jetty in 2013 and knocked off several people, “resulting in multiple injuries,” according to new research from the National Oceanic and Atmospheric Administration. The wave was what scientists call a meteotsunami.

An average of 25 meteotsunamis hit the East Coast each year, the researchers found. Similar to tsunamis that are caused by underwater earthquakes or landslides, meteotsunamis are driven by weather, according to NOAA.

“NOAA scientists determined these waves were part of a meteotsunami, a small, weather-driven tsunami caused by changes in air pressure created by fast-moving severe thunderstorms, tropical storms, squalls or other storm fronts,” NOAA said.

Research released this month looked at wave activity over 22 years along the eastern seaboard and found the coast sees an average of 25 mini-tsunamis each year. “Most are less than 1.5 feet high and relatively harmless. Only about one meteotsunami wave a year exceeds 2 feet in height, large enough to cause the injuries and destruction experienced in New Jersey,” NOAA said.

Meteotsunamis are most common on the East Coast during the summer because thunderstorms can create the right conditions to create the waves, the researchers found. They are also common in winter from nor’easters, the data show. The Carolinas, northern Florida and Long Island Sound see the most, researchers said.

“Myrtle Beach, South Carolina, and Duck, North Carolina, observed the greatest number of events: 148 (7.2 per year) and 130 (6.0 per year), respectively. Wrightsville Beach (8.7 per year) and Cape Hatteras (8.9 per year) in North Carolina had the highest averages per year for any station with at least five years of data,” according to NOAA.

King tides bring higher-than-average tides ashore through the year in South Carolina. The extreme tides occur when the moon passes close to the earth during it's orbit.

The researchers found evidence to suggest there were 548 meteotsunamis between 1996 and 2017, “including one that occurred during Hurricane Irma in 2017,” according to NOAA.

In a paper coming out this month in the journal Bulletin of the American Meteorological Society, researchers say they hope their findings can help detect meteotsunamis in the future before they hit land. “

“This work supports future meteotsunami detection and warning capabilities at 38 NOAA, including the development of an impact catalog to aid National Weather Service forecasters,” the researchers said in the journal article.

A 2,400-square-foot home on the Outer Banks is crumbling into the ocean near the Rodanthe Pier. Video shows part of the home's support structure being torn away by the waves. Video by Chicamacomico Banks Water Rescue

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Charles Duncan covers what’s happening right now across North and South Carolina, from breaking news to fun or interesting stories from across the region. He holds degrees from N.C. State University and Duke and lives two blocks from the ocean in Myrtle Beach.