Beaufort Scale

Answer.
Beaufort Scale is a scale used for measuring the strength or velocity of the wind. Various strengths are given in numbers. It was formulated in 1805 by the British Admiral Sir Francis Beaufort, and has been periodically revised since then. It ranges from Calm, when smoke rises vertically and the wind is less than 1 m.p.h (miles per hour) to Beufort number 12; at which occurs a hurricane, the air at sea is filled with foam and spray. During hurricane the wind exceeds 60 m.p.h