Chicago, IL

Watch Out for Tsunamis on Lake Michigan in Chicago This Summer

Natalie Frank, Ph.D.

Meteotsunamis happen frequently on Lake Michigan and can lead to devastating damage and loss of life.

Lighthouse hit by giant wave, Lake Michigan, on Wikimedia Commons (CC BY-SA 2.0)

Most people have likely seen videos of major tsunamis which cause massive loss of life and unbelievable destruction. Probably the tsunamis people are the most familiar with is the one that devastated Japan in 2011.

These massive waves may have been largely unknown to the public depending on where you lived, prior to the 2004 Boxing Day tsunami. That disaster occurred when an earthquake in the Indian Ocean triggered a series of huge waves which resulted in more than 230,000 deaths in 14 countries. Because of the widespread loss of life, and the ability to transmit reports and images around the world, people everywhere became aware of these massive waves and the damage they cause.

Tsunamis can be caused by any significant displacement of water in oceans or lakes. They are most frequently generated by the shifting of tectonic plates under the ocean floor when an earthquake occurs. They can also be caused by volcanic eruptions, glacial carving, meteorite impacts or landslides. The majority of tsunamis occur in the Pacific Ocean resulting from earthquakes in the areas “ring of fire”.

What most people aren’t aware of is that tsunamis can occur in very large lakes as well, and they occur regularly in the Great Lakes. Tsunamis on the Great Lakes might sound unlikely but they are real and at times have proven deadly.

Ocean tsunamis are usually caused by earthquakes when there is an abrupt upward thrusting of the Earth's crust which quickly displaces massive amounts of water. This leads to a large, long wave to form that builds in intensity as it moves across the ocean.

Tsunamis in large lakes work in much the same way however, the displaced water that starts them is created by sudden, high intensity storms causing winds or barometric pressure to push down with extreme force on the water. Because they are caused by meteorological conditions the resulting waves are called meteotsunamis.

Lake Michigan has the largest number of meteotsunamis out of all of the Great Lakes. While the majority are minor, at least in terms of the wave formations, there have been some on this lake that have caused loss of life. The three biggest accounted for 24 deaths.

  • On July 4, 1929, a 20-foot wave caused by a meteotsunami slammed into holiday beach-goers on a pier in Grand Haven. Ten people were pulled out into Lake Michigan and drowned.
  • On June 26, 1954, a 10-foot meteotsunami wave washed a group of fishermen off a pier on the shores of Lake Michigan in Chicago. Seven died.
  • On July 4, 2003, seven swimmers drowned within a 3 hour span following a severe thunderstorm that produced 50 mile per hour winds on Lake Michigan near Sawyer in Berrien County. They were attributed to meteotsunami waves and riptides caused by the wind and drop in barometric pressure.

Tsunami hits Lincoln Park, Chicago as man watches from high bridge Public Domain, Wikimedia (Public Domain)

Meteotsunamis in Lake Michigan

Like their ocean counterparts, meteotsunamis travel in a single direction across the water, though they do so after a significant weather event. While ocean tsunamis can be much bigger and more powerful, Great Lakes meteotsunamis can also be dangerous both as the wave crashes onto the shore and afterwards as the water is pulling back out again.

Usually, the situations that cause these tsunamis are a long line of thunderstorms or an organized group of long-lasting thunderstorms. The highest rates of occurrence of these types of meteorological events is during late-spring to mid-summer.

Researchers analyzed the frequency of meteotsunami event per year for all of the Great Lakes, determining that of an average 106 meteotsunamis that occur each year, the highest rates, 29 per year, occur in Calamet Harbor which is part of the Port of Chicago.

Waves May Not Be Big, But They Can Still Produce Deadly Rip Currents

While there are dozens of Meteotsunamis on Lake Michigan in the Chicago area every year, most people have likely never noticed them. They may have seen their high waves and thought they were regular big waves, or more likely, the waves may not have been big enough to cause attention. Most are one foot or less in height and are too small to notice.

While most of the waves don't end up causing severe damage and may be relatively small, Lake Michigan is notorious for dangerous rip currents, and a 2019 study found meteotsunamis, which can play a role in creating rip currents, present “severe water safety hazards and high risks, more frequently than previously recognized.”

In this study, it was determined that meteotsunamis, even those that are under a foot high, can be a strong generation mechanism for rip currents. According to Chin Wu, meteotsunami researcher with the University of Wisconsin-Madison rip currents formed by a single meteotsunami wave can last for hours afterward.

That is why the most dangerous time to go back into to water is within a few hours after a storm has passed. The meteotsunami wave is long gone, other normal waves have calmed done and the water may seem calm, but underneath, there’s a hidden danger in the form of extremely strong rip currents. They are so strong that the usual advice of swimming parallel to shore may not help a swimmer survive.

They are also extremely fast forming. The generated rip currents can change the nearshore conditions from calm to extremely hazardous in a matter of minutes due to the nature of fast-moving convective storms that create rapid changes in water level.

This hidden hazard can last for several hours, even when there are low energy wind wave conditions. Similar to tides, meteotsunamis can control the duration and spatial characteristics of different types of rip currents, dangerously broadening the range of nearshore areas that are affected life threatening rip currents.

Meteotsunamis Can Also Contribute to a Potential Nuclear Meltdown Near Chicago

Another problem that can occur relates to the nuclear reactors along Lake Michigan. Bradley Cardinale, director of the University of Michigan's Cooperative Institute for Great Lakes Research stated:

"When a tsunami recedes, it's sort of like a vacuum. We've got seven nuclear power plants that are literally on the shore of the Great Lakes. It could potentially pull water away from intake pipes, that keeps the core of thee nuclear reactors in check."

Of the seven plants (in the U.S.), five are along the shores of Lake Michigan. The Zion Nuclear Station is located just 50 miles north of Chicago, while the Palisades Nuclearn Station is just over twice that distance from Chicago.

Lack of Knowledge about Meteotsunamis Place Chicago and Other Illinois Communities at Risk

While water level changes are tracked by coastal communities as part of their resilience planning, research determined that the effects of meteotsunamis are not taken into consideration for planning or design along Lake Michigan. Additionally, though research has been conducted into warning models for approaching meteosunamis, the currently available forecast models are not sufficient for public safety efforts.

This research has also demonstrated the need for continued monitoring of existing Great Lakes water level gauges and perhaps additional ones as well. Coastal communities along Lake Michigan that might be impacted should work to educate their members about meteotsunamis and the potential danger they pose to human safety, and important infrastructure.

Here is a news report of a meteotsunami on Lake Michigan as it threatens Chicago. Many people don't seem to be taking it very seriously.

Here's another view of a Lake Michigan Tsunami taken by an amateur at Montrose Harbor, Chicago. You can really see the force of the waves here.

Please Be Careful

If you plan on visiting the Lake Michigan shore in Chicago this season, make sure to be extremely careful watching for storms that may quickly move in. Even if you don't see high waves, that doesn't necessirily mean that a tsunami isn't forming, and even small tsunamis that may seem like nothing can produce incredibly powerful rip currents that will drag you out into the lake before you know what's happening. Never swim alone, and alway have someone one shore watching you. Never swim in the lake in an area where there are no life guards no matter how good a swimmer you are.

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