Ice, Ice, Baby

Lake Michigan is icing in.  It is at 69% ice cover now.  http://www.glerl.noaa.gov/res/glcfs/glcfs-ice.php?lake=m&type=N&hr=00

The entire Great Lakes are over 80% covered in ice.  The one Lake holding down the percentage is Lake Ontario, which reached 40% ice coverage but is back down to 18%.  The dynamics  have to do with air temperature, water temperature and depth, and how far north the Lake sits.  Lake Erie, the shallowest lake, iced over first.  It frequently ices over because of its shallowness.  The shallowness means that there is not a reserve of warmer water.  Lake Michigan, for example, still has forty degree water out in the middle.   The next Lake to ice over was Lake Superior followed by Lake Huron.  Lake Michigan, with its forty degree water in the center, is at 69%.  The ice cover has been increasing at about 10% per week.  Water temperature and depth aren’t the only issues.  Some of the ice is a thin skim.  Wind can move the ice and open up water, depending on the ice thickness, and pile up the ice in ridges.  Bird watchers have been pleased when there is some open water because there are so many ducks hanging around as well as other water birds such as loons.

While birds need open water, everyone seems to agree that it is healthy for the Lake to freeze over now and again.  It allows any sediment to settle as there are no waves to churn up  the bottom.  The change in the water temperature will keep us cool into the summer.  The past several years  of  above average temperatures has meant residual heat was exhibited by higher water temperatures as well.  This winter may reset the water temperature, and the moderating affect from the Lake will be stronger next summer.  The longer the water stays cool, the more like it will be that next winter the Lake will have more ice cover.  It will provide some small protection against climate change.

The ice cover protects against evaporation and therefore helps to restore the Lake water levels.  Although not completely straight forward as noted in this study,

http://glisaclimate.org/media/GLISA_Lake_Evaporation.pdf

it is still a major influence.

Then there is the beauty of the ice.  Photographers and admirers are out every day, enchanted by the ever-changing formations.  The February light provides magnificent sunrises.  Those willing to brave the cold are  being rewarded by glorious sparkling ice visions.  It seems as if the dune restoration area and the Lake have become one, undulating out just to open water.  It is clear, between the drifts of snow  and the underlying drifts of sand, that these universal processes provide balm for the soul in all seasons.  Though winter seems the harshest, perhaps it is also the purest.

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