Roll Cloud - Duluth, Lester River, 1998 This baby came rolling over the hills of Duluth as I was driving home from work. I drove pretty fast along London Road to stay ahead of it and caught it just as it hit Lake Superior. Roll clouds are completely unattached from a parent storm cloud. This is what makes it distinctly different looking compared to a wall cloud or a shelf cloud. A roll cloud is long and tubular and appears to be "rolling" along a horizontal axis. Although you may think it looks like a tornado turned horizontal, it is not associated with tornadoes at all. Roll clouds form from outflow of the primary storm pressure-change zone. Roll clouds are pretty rare. They are most often associated with a gust front and do appear to roll or tumble. The wind behind this one was about 50 mph! October 12, 2005