The National Weather Service has a report available
A full assessment of the events of April 3, 2012 is not complete. However, we can review the NOAA/NWS/SPC historical tornado record for some insight into these recent tornado events in the DFW area.
Over the last 60 years (since 1952), a total of 172 tornadoes have been reported in either Tarrant or Dallas Counties, Texas. Of these, 42 have been rated at least EF2 (wind speeds over 110 mph). The strongest, rated EF4, hit Dallas on April 25, 1994, killing 3 people and injuring 48. Neither county has ever reported an EF5-rated tornado."
You can download (pdf) the report here: