The overwhelming majority of these reports originated from the Tennessee Valley and Southeast (about 25 originated from the D.C. metro region). While no other 24 hour period has experienced this many reports, it does not mean it was the most severe 24 hours on record. It could reflect increased reporting from National Weather Service officials, trained spotters, and emergency management officials. On the other hand, the number could still increase as severe weather reports are still coming in. Also note these reports are preliminary and may not have been fully quality controlled.
Nevertheless, the squall line associated with this weather system was remarkable for both its areal extent (at one point extending more than 900 miles) and intensity. The storm has been blamed for at least seven deaths.