A Supervisor from a Sub - Area shop near Greensburg , Kansas gave me a couple of photos in different stages of the Tornado that hit there and I was totaly amazed at the size and mass of that thing. He told me that at one point it reached the size of an EF6 . There was a storm chaser that was at the scene after the tornado ripped thru Greensburg that told the Supervisor that he thinks that it could of been the 1ST EF6 ever recorded, He said they figured it by the damage path and width path of the Tornado .