Lakeshore Flood Advisory

Bill's Blog
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A Lakeshore Flood Advisory will be in effect today thru 8 pm from Ottawa Co. to northern Indiana and from Manistee County to the north.  Get used to this.  With the high water levels, we are certainly susceptible to lakeshore flooding.  The situation is probably going to get worse before it gets better. 

Something to learn about waves:    Warm air going over cold water (like in spring and early summer) produces lower waves than cold air going over warm water.  A spring day with 80-degree air crossing Lake Michigan with a water temperature of 50 degrees and a 20 mph wind might produce 2-foot waves…while a fall day with 40 degree air coming over 60 degree water and a 20 mph wind may produce 6-foot waves. 

Strong onshore winds also push the water toward the shore.  That can cause the water level to rise even higher.  A steady 30 mph west wind might cause the water level to go up 6″ on the Michigan side of Lake Michigan and to drop 6″ at the Wisconsin shore.  This is called a “standing seiche“.

The lake levels are going to be high into the fall – the season of the “Gales of November” and that means we’ll continue to have the threat of lakeshore flooding, beach erosion and even moderate waves breaking over the piers and breakwaters. 

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