Developed by Sir Francis Beaufort in 1805 the Beaufort Wind Scale is now the standard by which all wind and storms are measured. The scale which is used to determine the wind speed starts at zero for calm and goes all the way to twelve for a hurricane. It was originally a system to estimate wind strengths without the use of any instruments; the affects on the ship that Sir Beaufort was in were what he originally measured.
Currently it is used for the same purpose of classifying wind strengths and also to tie together the various components of the weather into a united picture. The elements used are the strength of the wind and the state of the sea and the observable effects on the two.
Sir Francis Beaufort was born in the year 1774 in Ireland and joined the Royal Navy at the age of thirteen; he was a midshipman on the Aquilon and is said to have had a very impressive career. In 1805 he was made commander of the Woolwich, and it is during this time that he developed the Beaufort Wind Scale that is still in use today. The use of the Beaufort Wind scale was made mandatory for the log entries of all the ships in the Royal Navy by the year 1838.
The Beaufort Wind Scale is basically a set of integers with the description of the state of the weather. Beaufort felt there were thirteen levels of behavior he could recognize in the weather. Even though the descriptions used then are vague to sailors today they did give the full meaning of the wind force to the men he sailed with then. The heart of the scale is the effect of the winds on an eighteenth century fighting ship; after all that was what he was on at the time he developed the scale. The original intention was to look at the ship and not the wind.
When first developed it was 0 through 4 to describe the wind in relation to the speed at which it moved the ship. Five through nine was used to describe the mission and the carrying ability of the scale; ten through twelve was used to refer to the survival of the ship. Though other wind scales have been used none have lasted as long as the Beaufort Wind scale whose survival was helped with a disaster after the invention of the telegraph and the cup anemometer. After the loss of a shipment at sea weather warnings were put into place and the Beaufort Wind Scale began to grow in popularity.
Currently used to measure the wind itself there are only twelve levels to the scale. Zero is no wind or a calm wind. One is a wind speed of one to three miles per hour that is considered to be light air. Two is four to six miles per hour and a light breeze. A gentle breeze comes in at three on the scale with speeds of seven to ten miles per hour, next is moderate at four with eleven to sixteen mile per hour winds. The fresh breeze is at five with seventeen to twenty-one mile per hour winds.
Then the winds begin to pick up with a strong breeze of twenty-two to twenty-seven miles per hour coming in with a rating of five. The Near gale is at the seven rating with twenty-eight to thirty-three mile per hour winds, gales come in at eight with thirty-four to forty mile per hour winds.
The strongest four are at the bottom of the scale. Nine is forty-one to forty-seven mile an hour winds known as the strong gale; storm winds come in at number ten with forty-eight to fifty-five mile an hour winds. The next most severe is the violent storm at number eleven with winds from fifty-six to sixty-three miles per hour. The most violent winds are hurricanes at number twelve with winds of over sixty-three miles per hour.
If it were not for Sir Beaufort and his wind scale we probably would not have the advance storm warnings that we do today.
Sources:
http://www.spc.noaa.gov/faq/tornado/beaufort.html
http://weather.ncbuy.com/glossary.html?action=LETTER&term=B
http://www.weca.org/nws-terms.html
http://www.skegnesslifeboat.org.uk/info/beaufort.asp
