Beaufort windscale

1. Dia 1

mu

2. Dia 2

FORCE 0: CALM
MEAN WIND SPEED: LESS THAN 1 KNOT
Sea is like a mirror.

3. Dia 3

FORCE 1: LIGHT AIR
MEAN WIND SPEED: 1 - 3 KNOTS
Ripples with the appearance of scales are formed,
but without foam crests.

4. Dia 4

FORCE 2: LIGHT BREEZE
MEAN WIND SPEED: 4 - 6 KNOTS
Small wavelets, still short but more pronounced;
crests have glassy appearance and do not break.

5. Dia 5

FORCE 3: GENTLE BREEZE
MEAN WIND SPEED: 7 - 10 KNOTS
Large wavelets; crests begin to break; foam of
glassy appearance; perhaps scattered white horses.

6. Dia 6

FORCE 4: MODERATE BREEZE
MEAN WIND SPEED: 11 - 16 KNOTS
Small waves, becoming longer; fairly frequent
white horses.

7. Dia 7

FORCE 5: FRESH BREEZE
MEAN WIND SPEED: 17 - 21 KNOTS
Moderate waves, taking a more pronounced long form;
many white horses are formed (chance of some spray).

8. Dia 8

9. Dia 9

10. Dia 10

FORCE 6: STRONG BREEZE
MEAN WIND SPEED: 22 - 27 KNOTS
Large waves begin to form; the white foam crests are
more extensive everywhere (probably some spray).

11. Dia 11

FORCE 7: NEAR GALE
MEAN WIND SPEED: 28 - 33 KNOTS
The sea heaps up and white foam from breaking waves
begins to be blown in streaks along the direction of
the wind.

12. Dia 12

13. Dia 13

FORCE 8: GALE
MEAN WIND SPEED: 34 - 40 KNOTS
Moderately high waves of greater length; edges of
the crests begin to break into spindrift; foam is blown in
well-marked streaks along the direction of the wind.

14. Dia 14

FORCE 9: STRONG GALE
MEAN WIND SPEED: 41 - 47 KNOTS
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.

15. Dia 15

16. Dia 16

FORCE 10: STORM
MEAN WIND SPEED: 48 - 55 KNOTS
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 and shocklike; visibility affected.

17. Dia 17

18. Dia 18

FORCE 11: VIOLENT STORM
MEAN WIND SPEED:56 - 63 KNOTS
VIDEO
(click)
Phenominal
waves!!
Exceptionally high waves (small and medium sized ships
might be lost to view behind the waves); sea 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; visibility affected.

19. Dia 19

FORCE 12: HURRICANE
MEAN WIND SPEED: 64 KNOTS AND OVER
The air is filled with foam and spray; sea completely
white with driving spray; visibility very seriously affected.

20. Dia 20

FORCE 12:
Saffir/Simpson Scale - categories and damage.
Category 1: 64 - 83 knots
Damage: minimal.
Category 2 : 84 - 96 knots
Damage: moderate.
Category 3 : 97 - 113 knots
Damage: extensive.
Category 4 : 114 - 135 knots
Damage: extreme.
Category 5 : >136 knots
Damage: catastrophic.

21. Dia 21

The
International Maritime Language Programme – IMLP
C
The IMLP is an IMO-standard.
P.C. van Kluijven