The most common way of measuring wind force is with the Beaufort scale which defines a gale as wind from 50 kilometres per hour (14 m/s) to 102 kilometres per hour (28 m/s). It is an empirical measure for describing wind speed based mainly on observed sea conditions. On the original 1810 Beaufort wind force scale, there were four different \"gale\" designations whereas generally today there are two gale forces, 8 and 9, and a near gale 7:
The word gale is derived from the Middle English gale, a general word for wind of any strength, even a breeze. This word is probably of North Germanic origin, related to Icelandic gola (breeze) and Danish gal (furious, mad), which are both from Old Norse gala (to sing), from Proto-Germanic *galaną (to roop, sing, charm), from Proto-Indo-European *gʰel- (to shout, scream, charm away). One online etymology website suggests that the word gale is derived from an earlier spelling, gail, which it claims is of uncertain origin.
In 1806 he wrote in his log book a wind force scale. The scale was simple and very similar to one that Alexander Dalrymple had written in a book in 1789. A year later he added some criteria to the 0-12 scale that indicated how much of a ship's sails would be employed by a British man-of-war under each condition. It was not related to the speed of the wind.
In 1912 the International Commission for Weather Telegraphy sought some agreement on velocity equivalents for the Beaufort scale. A uniform set of equivalents was accepted in 1926 and revised slightly in 1946, extending the scale to 17 values (the added five values further refining the hurricane-force winds). By 1955, wind velocities in knots replaced Beaufort numbers on weather maps. 59ce067264