BEAUFORT SCALE OF WIND FORCE and BEAUFORT NOTATION
Beaufort Wind Force
Wind speed in:
Description Term
Sea Criterion
kts
m/s
Scale
Description
Height
0
< 1
0–0,2
Calm
Sea likes a mirror.
Calm (glassy)
1
1–3
0,3–1,5
Light air
Ripples with the appearance of scales are formed, but without foam crests.
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.
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
Slight
0,5–1,25
4
11–16
5,5–7,9
Moderate breeze
Small waves, becoming longer; fairly frequent with horses.
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)
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.
Very rough
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.
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
Ringabulina