Water is flooding the stadium from broken mains inside the place, caused by either structural damage...or as one newsie proposed, due to a massive pressure change in/around the dome associated with the tornado.
Trying to get some screen caps posted. There are some early images up here:
http://www.11alive.com/news/gallery/gallery.aspx?gid=112919&pid=1
Dang! Has the National Weather Service issued any kind of statement on the tornado? Do we have any idea as to the size of the funnel, wind speed, etc?