BEAUFORT SCALE OF WIND FORCE and BEAUFORT NOTATION

Beaufort Wind Force

Wind speed in:

Description Term

Sea Criterion

State of Sea

kts

m/s

Scale

Description

Height

0

< 1

0-0,2

Calm

Sea likes a mirror.

0

Calm (glassy)

0

1

1-3

0,3-1,5

Light air

Ripples with the appearance of scales are formed, but without foam crests.

1

Calm (rippled)

0-0,1

2

4-6

1,6-3,3

Light breeze

Small wavelets, still short but more pronounced, crests have a glassy appearance and do not break.

2

Smooth (vaveletes)

0,1-0,5

3

7-10

3,4-5,4

Gentle breeze

Large wavelets. Crests begin to break. Foam of glassy appearance. Perhaps scattered with horses

3

Slight

0,5-1,25

4

11-16

5,5-7,9

Moderate breeze

Small waves, becoming longer; fairly frequent with horses.

4

Moderate

1,25-2,5

5

17-21

8,0-10,7

Fresh breeze

Moderate waves, taking a more pronounced long form; many white horses are formed. (Chance of some spry)

5

Rough

2,5-4

6

22-27

10,8-13,8

Strong breeze

Large waves begin to form; the white foam crest are more extensive everywhere. (Probably some spry)

7

28-33

13,9-17,1

Near gale

Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind.

6

Very rough

4-6

8

34-40

17,2-20,7

Gale

Moderately-high waves of greater length; edges of crests begin to break into spindrift. The foam is blown in well-marked streaks along the direction of the wind.

7

High

6-9

9

41-47

20,8-24,4

Strong gale

High waves. Dense streaks of foam along the direction of the wind. Crests of waves begin to topple, tumble and roll over. Spry may affect visibility.

10

48-55

24,5-28,4

Storm

Very high waves with long overhanging crests. The resulting foam in great patches is blown in dense white streaks along the direction of the wind. On the whole the surface of the sea takes a white appearance. Tumbling of the sea becomes heavy and shock-like. Visibility affected.

8

Very high

9-12

11

56-63

28,5-32,6

Violent storm

Exceptionally-high waves. (Small and medium-sized 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 waves' crests are blown into froth. Visibility affected.

12

over 64

over 32,7

Hurricane force

The air is filled with foam and spray. Sea completely white with driving spray; visibility very seriously affected.

9

Phenomenal

over 14

Beaufort Letters

Weather

Beaufort Letters

Weather

Beaufort Letters

Weather

Beaufort Letters

Weather

b

Blue sky (0-1) clouded.

g

Gale (Beaufort force 8-9)

m

Mist

tlr or tls

Thunderstorm with rain or snow

bc

Sky partly (1-3) clouded.

G

Storm (Beaufort force 10)

o

Overcast sky

u

Ugly, threatening sky

c

Cloudy (more than 3 clouded)

h

Hail

p

Passing showers

v

Unusual visibility

d

Drizzle

jp

Precipitation in sight of station

q

Squally weather

w

Dew

e

Wet air (without precipitation)

kq

Line squall

r

Rain

x

Hoar frost

f

Fog

ks

Storm of drifting snow

rs

Sleet

y

Dry air

fg

Fog over sea (coast station)

kz

Sandstorm or dust storm

s

Snow

z

Haze

fg

Fog over low ground (inland station)

l

Lightning

t

Thunder

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