Meteotsunami impacting Lake Michigan along Chicago lakefront, Northwest Indiana after destructive storms

A meteotsunami is impacting Chicago's lakefront and the shore in Northwest Indiana Tuesday afternoon and evening after destructive storms in the area.

A meteotsunami is a change in water levels instead of an earthquake, driven by air pressure disturbances most often caused by thunderstorms and squalls.

When a massive storm complex like today moves through, large amounts of air rise off of the Earth's surface in advance of the storm, then drop back to the ground in and behind the storm. This causes large variations in atmospheric pressure, which can impact water levels.

A minor meteotsunami can cause water level fluctuations up to 2 ft, a severe one up to 6 ft. 

Tsunamis, by contrast, are driven by seismic activity, typically from earthquakes.

Following a line of extreme destructive thunderstorms, a meteotsunami is impacting Lake Michigan, all along Chicago's lakefront and the shore in Northwest Indiana. Waves between 3 and 6 feet will cover the bike path and walking paths in Chicago, and create generally very dangerous conditions along the lakefront.

There is a lakeshore flood warning until 5 p.m.   People are advised to avoid the lakefront until conditions are safer.

Meteotsunamis are not uncommon for the Great Lakes. In 2024, the Weather Channel reported an estimated 100 or so meteotsunamis in the region each year.