Standing Seiche on Lake MichiganOctober 28th, 2010 at 12:30 am by Bill Steffen under Bill's Blog, Weather
Thanks to Cort S. for finding this (click on link). If only we could harness the power of the wind! This is a data plot from Port Inland at the north end of Lake Michigan, east of Manistique. It shows the water level of Lake Michigan at that location. With this deep storm, we had strong SSW winds on Lake Michigan. This wind pushed the water up toward the north end of the lake. Note that the water level here rose about 20″!! The wind was so strong it pushed the water toward the north end of the lake with enough force to cause what we call a standing seiche (French word pronounced as a long “a”). I didn’t check it, but the water level probably dropped 10-20″ down toward Chicago. I’m sure this created a pretty fierce current of water moving out of Lake Michigan at the Mackinac Bridge (which by the way had wind gusts of 78 mph!) into Lake Huron. When a seiche occurs, rivers that empty into Lake Michigan can actually flow backwards if the water level of the lake goes up 20″! You can click on this graph to enlarge, but do click on the link, where you can see graphs of air pressure, temperature, and wind speed (look at how long the wind hung at about 40 knots (I knot is 1.15 mph) or better during the storm. Wouldn’t this have been nasty if it was winter and cold enough for snow!