Meteotsunami facts for kids

A meteotsunami is a giant sea wave that looks like a tsunami, but it's actually caused by weather events. Imagine a big wave that forms because of changes in the air pressure, not an earthquake or landslide.

Meteotsunamis happen when fast changes in barometric pressure (the weight of the air) push on a body of water. Unlike regular tsunamis, which come from sudden big events, meteotsunamis are created by moving weather systems. These can be severe thunderstorms, squalls, or storm fronts that quickly change the air pressure.

A meteotsunami often forms when bad weather moves at the same speed and in the same direction as the waves in the ocean, especially near the coast. The waves can get even bigger in places like shallow areas, bays, and inlets.

It can be hard to tell the difference between a meteotsunami and a regular tsunami, especially if there's no record of an earthquake. Only about 3% of known tsunami events in history are thought to be meteotsunamis. However, the real number might be higher because some past tsunamis have unknown causes. Meteotsunamis are also sometimes confused with seiche waves, which are long, standing waves that happen in enclosed or partly enclosed bodies of water.

What Makes Meteotsunamis Special?

Meteotsunamis are usually local events. They don't have as much energy as a huge tsunami caused by an earthquake. But they can still be dangerous if they get bigger due to something called resonance. This happens when the waves match the natural rhythm of a bay or harbor, making them grow.

These waves can last from a few minutes to several hours. Their size, length, and period (the time between waves) depend a lot on how fast and strong the storm front is. Meteotsunamis are moving waves that can affect both enclosed bays and large parts of the coastline. Some have even been over six feet tall, looking a lot like storm surge flooding.

How Often Do They Happen?

Meteotsunamis are more common than you might think! In April 2019, scientists found that about 25 meteotsunamis hit the East Coast of the United States every year. In the Great Lakes region, they happen even more often, with an average of 126 events each year.

Some places in the world experience them so often that they have special local names for them:

• Rissaga or rissague in Catalan
• Ressaca or resarca in Portuguese
• Milgħuba in Maltese
• Marrobbio or marrubio in Italian
• Seebär in German
• Abiki or yota in Japanese
• Šćiga in Croatian

Certain bodies of water are more likely to have meteotsunamis. This includes places where the natural rhythm of the water matches the incoming waves, especially long and narrow bays that line up with the direction of the waves. Good examples are Nagasaki Bay in Japan, the eastern Adriatic Sea, and the Western Mediterranean Sea.

Famous Meteotsunami Events

Meteotsunamis have caused damage and even fatalities in different parts of the world. Here are some notable examples:

In 1929, a six-meter wave in Grand Haven, Michigan, pulled ten people from the shore, and they sadly died. A three-meter wave hit the Chicago waterfront in 1954, sweeping people off piers and drowning seven.

On March 31, 1979, a meteotsunami in Nagasaki Bay reached a height of five meters, causing three deaths. In June 2013, a strong storm called a derecho off the New Jersey coast caused a widespread meteotsunami. Tide gauges along the East Coast, Puerto Rico, and Bermuda reported "tsunami-like" conditions. In New Jersey, a six-foot wave hit the Barnegat Inlet, pulling divers over a breakwater and sweeping three people off a jetty, seriously injuring two.

See also

In Spanish: Rissaga para niños

• Deep-ocean Assessment and Reporting of Tsunamis (DART)
• List of tsunamis
• Rogue wave
• Sneaker wave
• Storm surge
• Tsunami warning system (TWS)
• Undular bore