An EF1 tornado produces winds that can reach up to 112 miles-per-hour, the deadly tornado that struck Granbury was an EF4.
Texas Tech Associate Professor of Atmospheric Sciences Christopher Weiss said early forecast models didn't show any signs of tornadic potential, but that changed as the day progressed.
He said last night's storms are what researchers consider strong-scaled tornado events.
"The highest scale is five. So they are indicating the winds maybe short of 200 miles-per-hour that were responsible for the damage that was produced, and of course it is not just wind, that is also the items that are getting picked up in the wind," he said.
According to storm-spotters the twister near Cleburne was about a mile-wide.