A lone female occupant of a Kayak was engaged in white water rafting on the Potomac River in Maryland with a male companion in another Kayak.  Both Kayaks went over the falls on the turbulent river and one capsized.  The other subject frantically searched for her but she was later found wedged under a rock with multiple head and neck injuries.  NRP investigators are waiting the ME report but there does not appear to be any evidence of foul play.  Both persons were wearing helmets and PFDs.
Potomac