The Beaufort Scale
A Brief Biography

Francis Beaufort was born in 1774, in County Meath, Ireland, the son of Rev. Daniel Augustus Beaufort. He began his naval career at the young age of 13 as a cabin boy in the British Navy.

His interest in the weather began three years later and he started a meteorological journal, which he would continue until his death in 1857.

This journal developed into the first version of 'Wind Force Scale and Weather Notation', which he devised during his first command aboard H.M.S. Woolwich.

An injury in 1812 during a combined hydrographic study and patrol mission lead to him being ordered home by the Admiralty and he never returned to active sea duty although he remained in the British Navy.

In 1829 Beaufort was appointed Hydrographer to the Admiralty, and in 1838 his 'Wind Force Scale' was introduced by the British Navy for use in log entries.

In 1846 Beaufort was promoted to Rear Admiral, and was bestowed the title Knight Commander of the Bath two years later.

After 68 years of service, Beaufort retired from the Admiralty in 1855. He died two years later in 1857.
The Beaufort Scale
Beaufort
wind
force		 Mean
wind
speed in
knots		 Limits of
wind
speed in
knots		 Mean
wind
speed in
mph*		 Limits of
wind
speed in
mph*		 Descriptive
term
0 0 less than 1 0 less than 1 Calm
1 2 1 to 3 2 1 to 3 Light air
2 5 4 to 6 5 4 to 6 Light breeze
3 9 7 to 10 10 7 to 12 Gentle breeze
4 13 11 to 16 15 13 to 18 Moderate breeze
5 19 17 to 21 22 19 to 24 Fresh breeze
6 24 22 to 27 28 25 to 31 Strong breeze
7 30 28 to 33 35 32 to 38 Near gale
8 37 34 to 40 43 39 to 46 Gale
9 44 41 to 47 50 47 to 54 Strong gale
10 52 48 to 55 60 55 to 63 Storm
11 60 56 to 63 69 64 to 72 Violent storm
12 - 63 and above - 73 and  above Hurricane
*   Approx. conversion from values shown in knots.
Beaufort
wind force		 Land and sea
criterion
0 Smoke rises vertically
Sea like a mirror
1 Direction of wind shown by smoke drift, but not by wind vanes
Ripples with appearance of scales; no foam crests
2 Wind felt on face; leaves rustle; ordinary vanes moved by wind
Small wavelets; crests of glassy appearance; not breaking
3 Leaves and small twigs in constant motion; wind extends light flags
Large wavelets; crests begin to break; scattered whitecaps
4 Raises dust and loose paper; small branches move
Small waves, becoming longer; numerous whitecaps
5 Small trees in leaf begin to sway; crested wavelets form on inland water
Moderate waves, taking longer to form; many whitecaps; some spray
6 Large branches in motion; whistling heard in telegraph wires
Larger waves forming; whitecaps everywhere; more spray
7 Whole trees in motion; inconvenience felt when walking against wind
Sea heaps up; white foam from breaking waves begins to be blown in streaks
8 Breaks twigs off trees; generally impedes progress
Moderately high waves of greater length; edges of waves begin to break into spindrift; foam is blown into well marked streaks
9 Slight structural damage occurs; slates blown from roofs
High waves; sea begins to roll; dense streaks of foam; spray may reduce visibility
10 Seldom experienced on land; trees broken or uprooted; structural damage occurs
Very high waves with overhanging crests; sea takes white appearance as foam is blown in very dense streaks; rolling is heavy and visibility is reduced
11 Seldom experienced on land; trees broken or uprooted; considerable structural damage
Exceptionally high waves; sea covered with white foam patches; visibility still further reduced
12 Very rarely experienced on land; usually accompanied by widespread damage
Air filled with foam; sea completely white with driving spray; visibility greatly reduced

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