Of polar vortices and Great Lakes

30 Jan 2014

Photo courtesy of Space Science And Engineering Center- University of Wisconsin - Madison

Provided courtesy of Space Science and Engineering Center (SSEC), University of Wisconsin-Madison

A recent report tells us that evaporation isn’t well understood and that we may see more of it in the fall and early winter than in the summer.  According to the report, the relative humidity plays a bigger role than the temperature and as we know, it’s awfully dry in the winter. One quote from that report is staggering – “a 1-day loss of 0.5 inches of water from the total surface area of the Great Lakes represents a volumetric flow rate of 820 billion gallons per day – nearly 20 times the flow rate of Niagara Falls.”

The repeated polar vortices we have been experiencing have provided greater ice cover and, thus, there should be a later start to the evaporation season this year.  The Great Lakes are reportedly 62% covered in ice, which already ranks this winter as 17th most coverage in the last 40 years. 1979 had the highest ice cover at 94.7 percent.

Weatherwise, this high ice cover may mean less lake effect snow, colder days, less runoff when the snow melt comes (although it’s been a very snowy January) but again, less evaporation.

It’s certainly better (waterwise) to be here than, say, California, where Governor Brown declared a drought emergency which likely will have significant impacts on farming and the foods eaten across the United States.  This could be good for Michigan farmers.  2014 is already shaping up to be an interesting year for water and the Great Lakes.

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