Scale'' used universally to measure wind more than a hundred and fifty years ago.

Force Designation Velocity of Wind 0 Calm under 1 mph 1 light air 1-3 mph 2 light breeze 4-7 mph 3 gentle breeze 8-12 mph 4 moderate breeze 13-18 mph 5 fresh breeze 19-24 mph 6 strong breeze 25-31 mph 7 moderate gale 32-38 mph 8 fresh gale 39-46 mph 9 strong gale 47-54 mph 10 whole gale 55-63 mph 11 storm 64-75 mph 12 hurricane over 75 mph HURRICANES HUR