I saw the Jessica Savage movie....I believe it was a car accident. Her car flipped over in a river or something and she drowned.
I must be mixing her up with another female anchor who died in a plane crash . . . back in the 70s maybe? Very pretty if I remember.
Good link, describing both the famed broadcast and her death: http://www.findadeath.com/Decesed/s/Jessica%20Savitch/jessica_savitch.htm