This is the first time I've seen that particular video of the Cullman tornado, and it is fascinating. At the risk of stating the obvious, it seems like there are a lot of things going on all at once or in close proximity. Vortex breakdown is one. At times, the breakdown bubble is obvious--you can see a downdraft that appears to blow the tornadic circulation into multiple vortices, and I wonder if the downdraft doesn't fan out as it approaches ground level in a way that tilts vertical vortices into the horizontal, and/or perhaps interact with the updraft in a way that causes the same result. But there are also plenty of horizontal vortices that just seem to appear out of nowhere, and they seem to have nothing to do with vortex breakdown. This paper by Paul Markowski on vortex lines may offer a clue. As has been mentioned, it seems clear that the tornado is moving through an area that is surcharged with vorticity--which is what you'd expect, given the outrageous 1 km storm-relative helicities on April 27, 2011. In the Cullman video, it's interesting how some of the horizontal vortices rise while others sink. At around 5:10 in the video, the tornado assumes some fantastic shapes, and at 5:40, you can see a horizontal vortex form and then descend, slantwise, to ground level about a quarter-mile from the parent funnel. You have to wonder just exactly how one defines the periphery of such an extremely turbulent tornado that has got so much going on with it.