Meteotsunamis on the Great Lakes - WNEM TV 5

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Meteotsunamis on the Great Lakes

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Source: National Weather Service Source: National Weather Service

Around 4:31 AM (Eastern Standard Time), a 7.9 magnitude earthquake was detected around 280 kilometers (around 175 miles) southeast of Kodiak, Alaska.

Shortly after the earthquake was detected, tsunami warnings were issued for the Alaskan and Canadian coasts, along with tsunami watches for the west coast of the United States. As of late this morning, all watches, warnings, and advisories have been lifted. 

While scary for folks in Alaska and out west, and for those who have family in those regions, tsunamis aren't something that crosses the mind of many folks in Mid-Michigan. However, you might be surprised to learn we have our own tsunami-like phenomenon, and it's called a meteotsunami. 

So What Is A Meteotsunami?

According to the National Weather Service, a meteotsunami has similar characteristics to earthquake-generated tsunamis. But instead of being caused by earthquakes, they're caused by air-pressure disturbances, often associated with fast moving system such as a squall line. 

The fast moving disturbances can develop waves on the Great Lakes that move at the same speed as the weather system moving overhead. 

Like their earthquake generated counterparts, meteotsunamis can become dangerous when they move into shallow water and slow down, allowing them to build in height and intensity. 

The NWS says most of these meteotsunami events are too small to notice, but the largest can have big impacts such as damaging waves, flooding, and strong currents that can last for several hours. 

Some of these events also have the potential to be deadly. In June of 1954 in Chicago, seven people lost their lives as a 10-foot wave on Lake Michigan crashed into the shoreline, sweeping several people off of the pier. 

More recently, in 2012, a seven foot wave hit near Cleveland, sweeping those on the beach off their feet and swamping boats in the local harbors.

Want to know more about meteotsunamis and what's being done to forecast them? Check out this page from the National Weather Service: http://nws.weather.gov/nthmp/documents/meteotsunamis.pdf 

Isn't That A Seiche?

Seiches typically occur when strong winds and rapid changes in pressure push water from one end of a body of water to the other. When the wind finally subsides, the water is then able to move back to the other side. This would be similar to water sloshing back and forth in a swimming pool.

That water continues oscillating back and forth for hours, sometimes even days. 

So what's the difference? Meteotsunami events moves in one direction, unlike the sloshing motion of the seiche which moves back and forth. A seiche is also a longer duration event, with the time period between the high and low ends of the seiche sometimes as long as 4 to 7 hours. 

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