I'll be the first to admit I'm no geography whiz. I'd have a hard time identifying the exact location of several of our 50 states on a map, but I'm confident I'd at least be able to point to the right general area. At the very least, I am 100% certain that Wisconsin is not considered a "Northeast" state.
My guess is the article guy told the photo guy "Snow! We need a picture of snow!" and the photo guy said, "Hmm. Stock photos of snow. Better check Wisconsin." It's a safe bet, usually, I guess.