Beaufort Scale 9
Beaufort Scale 9 : Numerical scale from 0 to 12, indicating wind force. (1) light air, (2) light breeze, (3) gentle breeze, (4) moderate breeze, (5) fresh breeze, (6) strong breeze, (7) strong wind, (8) gale,(9) strong gale, (10) storm, (11) violent storm, (12) hurricane (Gunn 1990, 376; Reference Center 1998)