The Groan of Ice on a Lake When the Temperature Has Flirted with Zero All Week

So, I'm assuming that this is referring to the ice thawing, because I've never heard a frozen lake make this sound.
According to the Minnesota Climatology Working Group, lake ice actually starts to thaw from the bottom. (Did not know that!)

I am also thinking that maybe the colder climate of the more northern states make it possible to hear the lakes groan. (If you know, feel free to post a comment letting me know if my assumption is correct.)

That being said, here are some pictures of some lakes in the thawing process.