Getting serious Greensburg vibes from the videos from Mayfield. Just horrible. Worst-case scenario: a violent tornado consuming a town of some size in the middle of the night. Except Mayfield is considerably larger than Greensburg. Worst December tornado in the nation's history, perhaps, if these fatality estimates hold steady. The worst one I can think of previously was Vicksburg MS in 1953, 38 deaths.
EDIT: Here's an outbreak in 1957 that affected the same general area (bullseyed a little bit to the north of last night's) in mid December, and it included an F5:
https://en.wikipedia.org/wiki/Tornado_outbreak_sequence_of_December_18–20,_1957