It was not related to the speed of the wind. Over the following years he continued to use his scale in his logs. However, as ship design and the introduction of steam power became widespread even that scale had to be modified. In the International Commission for Weather Telegraphy sought some agreement on velocity equivalents for the Beaufort scale.
A uniform set of equivalents was accepted in and revised slightly in , extending the scale to 17 values the added five values further refining the hurricane-force winds. By , wind velocities in knots replaced Beaufort numbers on weather maps. Please Contact Us. Toggle navigation JetStream. Beaufort Wind Scale Wheel pdf 2. Disclaimer Information Quality Help Glossary. Small wavelets, still short but more pronounced, crests have a glassy appearance and do not break.
Large waves begin to form; the white foam crests are more extensive everywhere. Light winds at kph mph. Smoke drift shows wind direction. Light breeze at kph mph. Wind can be felt on face, flag ripples. Gentle breeze at kph mph. Flag waves. Paper and leaves are scattered. Fresh breeze at kph mph. Small trees sway, whitecaps form on waves. Strong breeze at kph mph. Umbrellas are hard to use, large branches on trees move.
Moderate gale at kph mph. Trees sway, walking in the wind is difficult. Fresh gale at kph mph. Twigs and branches break off of trees. Strong gale at kph mph. Roof tiles blow off buildings. Whole gale at kph mph. Trees are uprooted. Storm at kph mph. Hurricane at kph mph.
The Beaufort scale describes the force of winds. Photograph by Otis Imboden. Beaufort scale. Royal Navy. Sir Francis Beaufort. Media Credits The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
Last Updated Jan. Media If a media asset is downloadable, a download button appears in the corner of the media viewer. Text Text on this page is printable and can be used according to our Terms of Service. Interactives Any interactives on this page can only be played while you are visiting our website. Raises dust and loose paper; small branches moved. Small waves, fairly frequent white horses. Fresh Breeze. Small trees in leaf begin to sway; crested wavelets form on inland waters.
Moderate waves, many white horses. Strong Breeze. Large branches in motion; whistling heard in telegraph wires; umbrellas used with difficulty.
Large waves, extensive foam crests. Near Gale. Whole trees in motion; inconvenience felt when walking against the wind. Foam blown in streaks across the sea. Twigs break off trees; generally impedes progress. Wave crests begin to break into spindrift. Strong Gale. Slight structural damage chimney pots and slates removed.
Wave crests topple over, spray affects visibility. Seldom experienced inland; trees uprooted; considerable structural damage. Sea surface largely white. Violent Storm. Very rarely experienced; accompanied by widespread damage. Medium-sized ships lost to view behind waves. Sea covered in white foam, visibility seriously affected. Air filled with foam and spray, very poor visibility. The scale that carries Beaufort's name had a long and complex evolution from the previous work of others including Daniel Defoe the century before to when Beaufort was Hydrographer of the Navy in the s when it was adopted officially and first used during the voyage of HMS Beagle under Captain Robert FitzRoy , later to set up the first Meteorological Office Met Office in Britain giving regular weather forecasts.
In the early 19th century, naval officers made regular weather observations, but there was no standard scale and so they could be very subjective — one man's "stiff breeze" might be another's "soft breeze".
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