While looking for something on Google Earth I accidentally switched to the 1985 imagery, and found this view of northern Pennsylvania. The brown horizontal stripes are the scars from a series of massive (F4-F5) tornadoes that swept across the NE US and parts of Canada in 1985. The larger track is up to 2 miles wide, but luckily passed almost entirely through unpopulated forests.

Wikipedia has a great writeup on this event.