A WEATHER CHANNEL ARTICLE

Great Lakes: Where's the Ice?

by Tom Niziol, Winter Weather Expert

It's been a very mild winter for the most part across the Great Lakes Region.  

Temperatures are up, snowfall is down and if you like winter sports, everyone from skiers to ice fishermen are not happy.   

Speaking of ice fishing, the pastime is somewhat tenuous this year since there is so little ice on the Great Lakes.
   
Figure 1a is a chart that shows the average ice concentration on the Great Lakes during the first week of February and Figure 1b shows the concentration for this year.  As you can see, there is very little ice on the Great Lakes so far this year.  

 1973 - 2002 Average Great Lakes Ice Cover - First Week of February

Figure 1a: Median ice cover concentration during the first week of February 1973-2002. Image Credit: NOAA GLERL

 Great Lakes Ice Cover - Feb 2012

Figure 1b: Great Lakes Ice Cover February 5, 2012. The darker the colored areas of the Great Lakes, the more ice cover. Notice that the ice concentration of the majority of the Great Lakes is very little Image Credit: NOAA GLERL

For the most part the concentrations are just a bit behind what we normally would see, with the exception of Lake Erie. 

We will take a closer look at Lake Erie to see why it develops so much ice cover by early February and what it looks like this year.   

We decided to look at Lake Erie for a couple of reasons.  

Oh, I know it is the farthest south of the Great Lakes and you would think it should freeze up the latest.  

However, it is the shallowest of the Great Lakes as shown in Figure 2, therefore it has the least volume of water by far of any Great Lake.  

Therefore it tends to cool down and develop ice more quickly than any of the other lakes.   

 Cross Section of the Great Lakes

Figure 2: Cross section of the Great Lakes and St. Lawrence Seaway.  Notice how shallow Lake Erie (encircled) is compared to the rest of the Great Lakes. Image Credit:Natural Resources Canada

Lake Erie develops most of its ice cover in the first week or two of February while the deeper Great Lakes take most of the winter season to develop appreciable ice cover.   

I love to use polar orbiter satellite imagery to get a look at ice cover when the skies are clear.  Check out Figure 3a.  

 Lake Erie: Where's the Ice?

Figure 3a: Ice cover on February 3, 2012 across the eastern Great Lakes. Notice the turbidity in the water on Lake Erie but almost a total lack of ice cover. Image Credit: NOAA LANCE

This image, courtesy of NASA LANCE program, is a beautiful look at Lake Erie from February 1st, 2012, with the only ice at the very shallow west end of the lake.  

Compare this image to Figure 3b, from February 3rd, 2011 when the entire lake was frozen over.  

 Lake Erie: There's the Ice (in 2011)

Figure 3b: Ice cover on February 3, 2011 across the eastern Great Lakes.  Notice that Lake Erie is completely iced over, and fresh snow cover highlights the other geographic features around each lake Image Credit: NOAA LANCE

This begs the next question, "If Lake Erie has so little ice cover, does it mean that we will get a lot more lake effect snow when cold air comes down across the lake?"  Well, this is a tricky one because the whole process is a bit self-defeating.

See, if you bring arctic air across shallow Lake Erie, it might produce a significant lake-effect snow storm, but the presence of arctic air will cause the shallow lake to cool and eventually develop ice cover.  



http://www.weather.com/outlook/weather-news/news/articles/great-lakes-lacking-ice_2012-02-06