THE PLT REPORTED THAT WHILE ON SHORT FINAL AT AN AIRSPEED OF 80 MPH WITH FLAPS EXTENDED, THE ACFT EXPERIENCED A SUDDEN LOSS OF ALT. THE ACFT DESCENDED RAPIDLY AND CONTACTED THE RWY FROM AN ALT OF APRX 10 FT AGL. THE LANDING WAS BEING MADE ON RWY 13 AND THE PLT REPORTED LOCAL WINDS FROM 180 DEGS AT 5 KTS GUSTING TO 10 KTS.