Last Thursday night, a intense line of storms moved along the Gulf Coast, producing 70 mph winds in many places, including Fort Morgan, AL. The system was most intense in Louisiana. Off the coast of Louisiana, air pressure changes and wind changes in the storms were enough to cause a large ocean wave known as a meteotsunami. This is a tsunami, or large ocean wave, caused by meteorological factors. It was measured along the coast. The most intense readings occurred at Calcasieu Pass in Louisiana, near Lake Charles. There, the wave brought water 5 feet above normal tide, then the water dropped 7 feet. The tide gauge data and a picture is shown below.
Intense meteotsunamis are rare, but have been known to occur in the U.S. One occurred in 1954 in Chicago (Lake Michigan) and caused fatalities as people were swept off piers. The height of the wave depends not only on the pressure and wind, but also on the depth of the water (at the perfect depth, resonance occurs).
Dr. Tim Coleman