The intense northerly winds that blew through the Great Lakes region late last week, caused the silt in the southern portion of Lake Michigan to become churned up, increasing the lake turbidity to extremely high levels. The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA's Terra polar orbiting satellite captured this high resolution image over Lake Michigan around noon on Sunday, October 2, 2011. Note how the "muddy" waters get caught in the currents moving through the lake.
The animation below shows the evolution of the "silt plume" over a four day period,from Oct 1 through Oct 4, 2011
The next image is courtesy of National Weather Service Chicago, it is an estimate of the peak wave heights across Lake Michigan during the high winds.