This event may have been briefly comparable to a US style tornado in upper scale but probably not a May 3 1999 Oklahoma City or Joplin style event. We are still talking paramaeters being sketchy for the day and I agree with Michael Thomas and David Croan in terms of downplaying the event a slight touch perhaps F3 to F5 range.
If trajectories on this day were from the NW, then definitely not. I would perhaps suggest there were quite a few supercells on this day.
And yes, such events are quite rare in this country in my opinion. Tornadic events of varying intensities and significance are simply part of the Great Plains climate!