What is a Meteotsunami?
The Great Lakes are huge bodies of water capable of generating substantial wave activity—people even surf on Lake Superior! But were you aware that tsunamis are among the types of wave events that occur in the Great Lakes? The term tsunami usually refers to waves caused by displaced water when the underlying earth shifts or slides.
Although the Great Lakes region is relatively geologically inactive, the lakes are not exempt from a different kind of tsunami: Meteotsunamis are caused by meteorological events and result in a wave that has a very similar physical nature to a seismic tsunami wave, but on a much smaller scale. Fast moving storms resulting in sudden changes in barometric pressure over the lakes can cause displacement of significant amounts of water creating a large wave that can travel long distances and affect large areas of coastline.
Update: model output is here! Check out this GIF of not one, but TWO meteotsunamis that came across the lake on Friday the 13th. Red = higher water level, blue = lower. pic.twitter.com/zjTZXRquNA
— NOAA Great Lakes Environmental Research Laboratory (@NOAA_GLERL) May 11, 2018
Predicting and Preparing
Like traditional seismic tsunamis, meteotsunamis result in rapid changes in water levels at coastlines that can take people by surprise, sometimes causing structural damage and even sweeping people out into stormy waters with intense currents. For this reason, Great Lakes researchers are working on developing a system that will allow them to predict when meteotsunamis could occur and where they might hit.
Scientists now know what type of storm events are capable of generating meteotsunamis but existing sensors are not capable of collecting real-time data quickly enough to detect all rapid air pressure changes—changes that may only last a few minutes. The Cooperative Institution for Great Lakes Research is providing funding to set up 29 real-time high frequency sensors around Lakes Erie and Michigan for a pilot project in predicting meteotsunamis on the Great Lakes. To learn more about this project check out this article by Jim Erickson on the University of Michigan News website.
The article by Jim Erickson points out that seiches are a different phenomenon than meteotsunamis, associating seiches with both air pressure differential and, more significantly, wind. Oftentimes, meteotsunamis are mistaken for the more well-known seiche. In June and early July, rapidly rising water in the Thunder Bay and Rossport area, when local weather was relatively calm, ripped out and scattered docks, which begs the question: could that have been a meteotsunami?