Most people know tsunamis as giant waves set off by earthquakes. But the weather can make them too. Meteotsunamis are large waves driven by the air-pressure disturbances that come with fast-moving storms — severe thunderstorms, squalls and other storm fronts — and scientists are only beginning to understand them well.
How a storm makes a wave
Unlike tsunamis triggered by seismic activity, a meteotsunami starts in the air. The storm generates a wave that travels toward shore, where a shallow continental shelf and an inlet, bay or other coastal feature can amplify it. Meteotsunamis have been observed at heights of 6 feet or more, and they occur in many places — the Great Lakes, the Gulf of America, the Atlantic Coast, and the Mediterranean and Adriatic Seas. Stormy weather can set off a series of these waves, typically much smaller and less destructive than earthquake tsunamis.
Easy to mistake for something else
A meteotsunami is hard to identify, because it looks almost exactly like a seismic tsunami. It can also be confused with wind-driven storm surge or with a seiche. That uncertainty makes meteotsunamis hard to predict and warn about. NOAA scientists have identified atmospheric conditions likely to generate one and are working on ways to forecast them.
Seiche or meteotsunami?
The two are often grouped together, but they are different events, and sometimes both happen at once:
| Seiche | Meteotsunami | |
|---|---|---|
| Main driver | usually wind | air pressure often plays a large role |
| Kind of wave | a standing wave | a progressive wave |
| Wave period | longer — typically three hours or more | two minutes to two hours, the tsunami band |
| Where | usually partly or fully enclosed basins, such as Lake Erie | enclosed basins, but also common on the open coast; one can travel far and affect a long stretch of coastline |
Sources
Based on "What is a meteotsunami?" from NOAA's National Ocean Service, a work of the United States government in the public domain.
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