Figure 6. Monthly mean Lake Michigan water levels at Ludington, Michigan. 



2. Lake Ice. 



Lake ice, which builds up along the shore during the winter months (Fig. 

 7), provides valuable beach protection which offsets the effects of winter 

 storms. The period and the amount of ice coverage vary both yearly and with 

 location. Ice tends to develop in late December and persists into March. 



A thorough analysis of the development, buildup, and eventual disappear- 

 ance of shore ice during the 1973-74 winter was done by Seibel, Carlson, and 

 Maresca (1975) in conjunction with the construction of the Donald C. Cook 

 Nuclear Power Plant in Berrien County, Michigan. Davis (1973) also discussed 

 lakeshore ice. 



3. Storms. 



Storms that affect the study area generally move through the Great Lakes 

 from west to east. The combination of this path and counterclockwise circu- 

 lation produces strong winds from the north and northwest usually following 

 passage of the storm. Seibel (1972), Maresca (1975), Davis (1976), and others 

 have investigated in detail the wind and wave climate of the study area and 

 the characteristics of the storms which affect the eastern shore of Lake 

 Michigan. 



Seibel (1972) determined that the average annual number of low-pressure 

 storm systems, regardless of magnitude, was about 43, although the number 

 varied from a low of 31 storms to a high of 67 storms (from 1938 to 1970) with 



15 



