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The Beaufort Wind Scale

Force

Speed (knots)

Speed (kmh)

State

Wave Height (metres)

At Sea

Cuppa Scale

Action of
Sailing Ship

 

 

On Land

0

0

0

Calm

Nil

Sea like a mirror

Cool drink and snooze

Makes no headway

Force0

Force 0

Calm, smoke rises vertically 

1

1-3

1-5

Light air

<0.1

Ripples with the appearamce of cales are formed, but without foam crest

Another cool drink, quiet read Just has headway

Force1

Force 1

Smoke drifts, wind vanes do not move

2

4-6

6-11

Light breeze

0.1 - 0.3

Small wavelets, still short but more pronounced; crests have a glassy appearance and do not break Put down glass to hold magazine page Wind fills sails; makes up to 2 knots

Force2

Force 2

Wind felt on face, vanes move, leaves rustle

3

7-10

12-18

Gentle breeze

0.3 - 0.9

Large wavelets, crests breaking, scattered whitecaps Keep an eye on drink and put magazine down perhaps Heels slightly under full canvas; makes up to 3 knots

Force3

Force 3

Leaves and small twigs in constant motion, light flags flap

4

11-16

19-30

Moderate breeze

0.9 - 1.5

Small waves becoming longer, numerous whitecaps Drink is slightly awkward, read chart Good working breeze; under all sail; heels considerably

Force4

Force 4

Dust, leaves, loose paper raised up, small branches move

5

17-21

31-39

Fresh breeze

1.5 - 2.5

Moderate waves of longer form, many whitecaps, spray Spill remaining drink, hold chart firmly Shortens sail

Force5

Force 5

Small trees in leaf begin to sway, flags fully extended

6

22-27

40-50

Strong breeze

2.5 - 4

Larger waves, whitecaps everywhere, more spray Cup of tea would be nice, sit on chart Double-reefs mainsail

Force6

Force 6

Larger branches of trees in motion, whistling heard in wires, umbrellas difficult to use

7

28-33

51-61

Moderate gale

4- 6

Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind Cup slides in saucer, chart a little damp and stained Remains in harbour, or if at sea, lies to.

Force7

Force 7

Whole trees in motion, resistance felt when walking

8

34-40

62-74

Fresh gale

6 - 8

Moderately high waves of greater length; edges of crests begin to break into the spindrift; the foam is blown in well marked streaks along the direction of the wind Hot tea in a mug then, if anyone’s making one Takes shelter if possible

Force8

Force 8

Twigs and small branches break off trees, progress generally impeded

9

41-47

75-87

Strong gale

8 - 10

High waves; dense streaks of foam along the direction of the wind; crests of waves begin to topple; tumble and roll over; spray may affect visibility Mug of hot tea would have been very nice….

-

Force9

Force 9

Slight structural damage, slates blown off roofs

10

48-55

88-100

Whole gale

10 - 12

Very high waves with long overhanging crests; foam in great patches is blown in dense white streaks along the direction of the wind; the surface of the sea takes a white appearance, the tumbling of the sea becomes heavy rolling sea; visibility affected Hard to keep mug at lips, some may spill down chin on to remains of chart

-

Force10

Force 10

Trees broken or uprooted, structural damage, boats break free from moorings

11

56-63

101-117

Storm

12 - 16

Exceptionally high waves (small and medium size ships might be for a time lost to view behind the waves); the sea is completely covered with long white patches of foam lying along the -direction of the wind; everywhere the edges of the wave crests are blown into froth; very poor visibility Holding mug properly now focuses one’s whole attention and chart hard to read anyway

-

Force11

Force 11

Wide spread structural damage

12

>64

>118

Hurricane

>16

Air filled with foam, sea completely white with driving spray; visibility very seriously affected

Tea may be salty

-

Force12

Force 12

Violence and destruction. Massive and widespread damage to structures.

 

Admiral Beaufort

The Beaufort Scale was invented by Admiral Francis Beaufort. The Beaufort Scale describes the various wind velocities. It gets its name from a British Admiral, Sir Francis Beaufort (1174 - 1857), who created the scale around the year 1805 on the basis of the effect of wind on a sailing ship. Like most sailors he noticed that the various sea states were closely related to the wind strength. But he obviously had a lot of time to observe and think about it!

(The above chart is a compilation of information from various sites. Thank you for your contribution.)