The snow in the upper Midwest last week highlighted several interesting features in the landscape.  One of them was a tornado path from an EF3 tornado that traveled along a 40 mile long path through a forested area northwest of Green Bay, Wisconsin in 2007.  The Weather Channel has a nice video and write-up of this here.  As the article points out, you can see these features in many areas, but the combination of snow and a path through a forested area really brought this path out.  There are many similar paths in the Southeast, but since continuous forest cover is infrequent in the Southeast, they are harder to spot.

Source: NASA
Source: NASA