3.5 Wind-Generated Waves
93
Table 3.1: The Beaufort Wind Scale (adapted from Bearman, 1997)
o Calm
1 Light air
Wind speed
State of the sea-surface
H
knots
< 1
1- 3
m/s
(m)
0.0- 0.2 Sea like a mirror
0
0.3- 1.5 Ripples with appearance of 0.1-0.2
waves;
2 Light breeze
4- 6
3 Gentle
7-10
breeze
1.6- 3.3 Small wavelets;
0.3-0.5
3.4- 5.4 Large wavelets; crests begin 0.6-l.0
to break;
4 Moderate
11-16
5.5- 7.9 Small waves becoming longer;
1.5
breeze
frequent white horses;
5 Fresh breeze 17-21
8.0-10.7 Moderate waves taking longer
2.0
6 Strong
breeze
7 Moderate
gale
8 Fresh gale
9 Strong gale
10 Whole gale
11 Storm
12 Hurricane
form;
22-27 10.8-13.8 White foam crests extensive
everywhere;
28-33 13.9-17.1 Sea heaps up and white foam
from breaking waves begins to
be blown in streaks;
34-40 17.2-20.7 Moderately high waves of
greater length; edges of crests
break into spindrift;
41-47 20.8-24.4 High waves, sea begins to roll;
48-55 24.5-28.4 Sea-surface takes on white appearance as foam in great
patches is blown in very dense
streaks;
56-64 28.5-32.7 Exceptionally high waves; sea
covered with white patches of
foam, visibility reduced;
3.5
5.0
7.5
9.5
12
15
>64
>32.7 Air filled with foam and spray >15
visibility greatly reduced
BO denotes the Beaufort wind scale.