Modern Beaufort scale
Beaufor
Descriptio
t
n
number
Wave
Wind
Sea
heigh
speed
conditions
t
<
1 km/h
(<
0m
0.3 m/s)
0
Calm
Flat.
< 1 mph
Land conditions
Calm. Smoke rises
vertically.
< 1 kn
< 0.3
m/s
1
2
Light air
Light
breeze
0 ft
1.1–
5.5 km/
h (0.3– 0–0.2
2 m/s) m
Ripples
1–
without
3 mph
crests.
1–2 kn
0–1 ft
0.3–
1.5 m/s
5.6–
11 km/h
(2–
0.2–
3 m/s) 0.5 m
4–
7 mph
3–6 kn
Small
wavelets.
Crests of
glassy
appearance,
not breaking
Smoke drift indicates
wind direction and
wind vanes cease
moving.
Wind felt on exposed
skin. Leaves rustle
and wind vanes begin
to move.
1–2 ft
1.6–
3.4 m/s
3
4
Gentle
breeze
Moderate
breeze
12–
19 km/h
(3–
0.5–1 Large
5 m/s) m
wavelets.
Crests begin
8–
to break;
12 mph
scattered
7–10 kn
whitecaps
2–
3.4–
3.5 ft
5.4 m/s
20–
28 km/h
(6–
1–2
8 m/s) m
13–
17 mph
11–15
kn
3.5–
6 ft
5.5–
7.9 m/s
Small waves
with
breaking
crests.
Fairly
frequent
whitecaps.
29–
38 km/h
(8.110.6 m/s 2–3
m
)
5
6
Fresh
breeze
Strong
breeze
Moderate
waves of
some length.
Many
18–
whitecaps.
24 mph
Small
16–20
amounts of
kn
6–9 ft spray.
8.0–
10.7 m/s
39–
49 km/h
3–4
(10.8m
13.6 m/s
)
Long waves
begin to
form. White
foam crests
are very
Leaves and small
twigs constantly
moving, light flags
extended.
Dust and loose paper
raised. Small
branches begin to
move.
Branches of a
moderate size move.
Small trees in leaf
begin to sway.
Large branches in
motion. Whistling
heard in overhead
wires. Umbrella use
becomes difficult.
Sea state photo
Associated Warning
Flag
25–
30 mph
21–26
kn
9–
13 ft
10.8–
13.8 m/s
7
frequent.
Some
airborne
spray is
present.
50–
Sea heaps
61 km/h
up. Some
(13.9foam from
16.9 m/s 4–5.5 breaking
m
)
waves is
High wind,
blown into
Moderate 31–
streaks
38
mph
gale,
along wind
Near gale 27–33
direction.
kn
13– Moderate
19 ft amounts of
13.9–
airborne
17.1 m/s
spray.
8
Moderately
high waves
with
breaking
crests
forming
39–
spindrift.
46 mph
WellGale,
34–40
marked
Fresh gale kn
streaks of
foam are
18– blown along
25 ft wind
17.2–
direction.
20.7 m/s
Considerabl
e airborne
spray.
9
75–
High waves
88 km/h
whose crests
(20.8sometimes
7–10
24.4 m/s
roll over.
m
)
Dense foam
is blown
47–
along wind
54 mph
direction.
41–47
Large
kn
amounts of
23– airborne
32 ft spray may
20.8–
begin to
24.4 m/s
reduce
visibility.
Empty plastic
garbage cans tip over.
Whole trees in
motion. Effort needed
to walk against the
wind.
62–
74 km/h
(17.220.6 m/s 5.5–
7.5 m
)
Strong
gale
89–
102 km/
h (24.7- 9–
28.3 m/s 12.5
)
m
55–
63 mph
10
Very high
waves with
overhanging
crests. Large
patches of
foam from
wave crests
give the sea
48–55
a white
kn
Storm,
appearance.
Whole gale
Considerabl
e tumbling
of waves
29– with heavy
41 ft impact.
24.5–
28.4 m/s
Large
amounts of
airborne
spray reduce
visibility.
11
Violent
storm
Some twigs broken
from trees. Cars veer
on road. Progress on
foot is seriously
impeded.
Some branches break
off trees, and some
small trees blow over.
Construction/tempora
ry signs and
barricades blow over.
Trees are broken off
or uprooted, saplings
bent and deformed.
Poorly attached
asphalt shingles and
shingles in poor
condition peel off
roofs.
103–
11.5– Exceptionall Widespread damage
117 km/ 16 m y high
to vegetation. Many
h (28.632.5 m/s
)
waves. Very
large
patches of
foam, driven
64–
before the
72 mph
wind, cover
56–63
much of the
kn
sea surface.
Very large
37– amounts of
52 ft airborne
28.5–
spray
32.6 m/s
severely
reduce
visibility.
roofing surfaces are
damaged; asphalt
tiles that have curled
up and/or fractured
due to age may break
away completely.
≥
118 km/
h (≥
32.8 m/s ≥ 14
m
)
Huge
waves. Sea
is
completely
≥ 64 kn
white with
foam and
Hurricane
spray. Air is
Force
filled with
driving
spray,
≥
≥
46 ft greatly
32.7 m/s
reducing
visibility.
≥
73 mph
12
Very widespread
damage to vegetation.
Some windows may
break; mobile homes
and poorly
constructed sheds and
barns are damaged.
Debris may be hurled
about.
The scale is used in the Shipping Forecasts broadcast on BBC Radio 4 in the United Kingdom, and in the Sea Area Forecast from
Met Éireann, the Irish Meteorological Service. Met