Can a tsunami occur on the Great Lakes?
A meeting happening in Ann Arbor this week has brought attention to a Great Lakes risk many don't know about or fully understand.
Tsunamis on the Great Lakes are very real, BUT they are different from what you might be thinking of.
FIRST, there are 2 events where water rises dangerously: A seiche and a meteotsunami.
WHAT IS A SEICHE?
A seiche is an oscillation of water in an enclosed area like a lake.
Storms, strong winds, or a change in atmospheric pressure causes water to push from one side of the lake to the other.
The water then floods back to the original side, like the water swishing back and forth in a bathtub.
This oscillation is called a seiche and can cause flooding and damage along the shoreline of the lakes.
WHAT IS A METEOTSUNAMI?
Simply put, a meteotsunami is a tsunami that occurs due to weather conditions and NOT from an earthquake.
High winds or a quick change in air pressure can cause these so they are very similar to a seiche in this regard.
Meteotsunamis are not as large as tsunamis caused by earthquakes.
They are very real and according to the Michigan State University Extension and National Weather Service, an average of 106 a year occur on the Great Lakes.
Water floods in one direction and does not oscillate back like a seiche does.
DIFFERENCE BETWEEN A SEICHE AND A METEOTSUNAMI:
There a couple of major differences between each event.
A seiche oscillates back, sloshing across the lake while a meteotsunami does not and only floods in one direction.
The other major difference is the duration of each.
According to the MSU Extension, a seiche can take up to 4-7 hours to go from the high to low water level.
A meteotsunami occurs in minutes, extremely quickly in much the same way a tsunami generated by an earthquake would.
It is highly likely that multiple recordings of a seiche were actually meteotsunamis and have been incorrectly recorded.
Experts are meeting this week to determine a way to warn people along the coast of these events.
Hopefully this clears up the confusion on what the difference is between these water-based phenomenons.