The Great Lakes of the United States were 88% ice covered as of mid-February 2014. That is the largest extent since 1994. Since 1973, the average ice coverage is 51%. This is only the fifth time in 40 yrs that it has exceeded 80%. The least extent during that time was 9.5% in 2002. Ice started forming in some of the bays and inlets in November instead of mid-December because of an unusually cold fall season.
This image was taken February 19, 2014. It was recorded by the Moderate Resolution Imaging Spectro-radiometer (MODIS) on NASA’s Aqua satellite. Visible are snow cover, darker grey forested areas, clouds, ice, and some open water as black. Click on this and the next image if you want to see a very large version 5200×4000 pixels. You need a fast internet connection.
This image recorded the same scene in infrared and red wavelengths to help discern snow, water, and clouds. Pale blue is ice. Navy is open water. Snow is blueish green. Clouds are white in most cases. Some clouds with high ice content appear blueish green.
The ice extent, among other things, is monitored daily by the Great Lakes Environmental Research Laboratory. The current ice extent is 85.4%.
Does this large extent of ice have other impacts? The answer is yes.
- Lake effect snows are decreased. Cities like Buffalo, NY, and South Bend, IN, usually receive massive amounts of snow each winter from lake effects. Air blows across open waters upwind and becomes more laden with moisture. When it comes ashore, it chills quickly and precipitates out as heavy snow. The larger extent of lake ice this year will help to reduce those snows.
- The large extent of ice helps to reduce evaporation. This could help to keep the lake level a little higher and help with water supplies for cities that use the lake.
- Shipping and recreational use would also benefit by the higher water levels.