In honor of the current weather, the Beaufort Wind Scale:
|Appearance of Wind Effects|
|On the Water||On Land|
|0||Less than 1||Calm||Sea surface smooth and mirror-like||Calm, smoke rises vertically|
|1||1-3||Light Air||Scaly ripples, no foam crests||Smoke drift indicates wind direction, still wind vanes|
|2||4-6||Light Breeze||Small wavelets, crests glassy, no breaking||Wind felt on face, leaves rustle, vanes begin to move|
|3||7-10||Gentle Breeze||Large wavelets, crests begin to break, scattered whitecaps||Leaves and small twigs constantly moving, light flags extended|
|4||11-16||Moderate Breeze||Small waves 1-4 ft. becoming longer, numerous whitecaps||Dust, leaves, and loose paper lifted, small tree branches move|
|5||17-21||Fresh Breeze||Moderate waves 4-8 ft taking longer form, many whitecaps, some spray||Small trees in leaf begin to sway|
|6||22-27||Strong Breeze||Larger waves 8-13 ft, whitecaps common, more spray||Larger tree branches moving, whistling in wires|
|7||28-33||Near Gale||Sea heaps up, waves 13-19 ft, white foam streaks off breakers||Whole trees moving, resistance felt walking against wind|
|8||34-40||Gale||Moderately high (18-25 ft) waves of greater length, edges of crests begin to break into spindrift, foam blown in streaks||Twigs breaking off trees, generally impedes progress|
|9||41-47||Strong Gale||High waves (23-32 ft), sea begins to roll, dense streaks of foam, spray may reduce visibility||Slight structural damage occurs, slate blows off roofs|
|10||48-55||Storm||Very high waves (29-41 ft) with overhanging crests, sea white with densely blown foam, heavy rolling, lowered visibility||Seldom experienced on land, trees broken or uprooted, “considerable structural damage”|
|11||56-63||Violent Storm||Exceptionally high (37-52 ft) waves, foam patches cover sea, visibility more reduced|| |
|12||64+||Hurricane||Air filled with foam, waves over 45 ft, sea completely white with driving spray, visibility greatly reduced|| |
Devised by Rear Admiral Sir Francis Beaufort in 1805 to standardize weather observations by ships at sea. Beaufort’s scale was officially adopted in the 1830s when Sir Francis was British Admiralty Hydrographer of the Navy. Beaufort invited Charles Darwin to accompany Captain FitzRoy on a survey voyage; that voyage saw the first official use of the Beaufort Scale.
Originally the scale’s observations depended on the appearance of a ship’s sails (0: All sails hang loose—12: All sails close reefed). With the advent of steam the observations were changed to the appearance of the sea. In the 1850s observations of flags and trees were added for stations ashore.
While the Beaufort Scale has been generally replaced by observations of true wind speed using instruments, today’s storm warnings still follow Beaufort’s nomenclatures.