At last count, 165 tornado reports were being investigated that lead to 300 deaths across several states - mostly in Alabama. A combination of violent conditions provided a balance of instability and incredible shear for steady state and long lived and long tracked deadly tornadoes. EF 5 damage has been documented amongst some of these tracks.
http://www.youtube.com/watch?v=9M_mcOL99qA&NR=1
http://www.youtube.com/watch?v=5sZJBxHiCRs&feature=player_embedded