|
Beaufort Scale Force
|
Wind MPH
|
Wind Knots
|
Wind Km/h
|
Wind in m/s
|
Description - Wave Heights-Visible Condition
|
|
Force 0
|
0-1
|
0-1
|
0-1
|
0
|
Calm; Ht 0.0m ~ At sea no waves - glassy like appearance
of sea. On land smoke rises vertically.
|
|
Force 1
|
1 - 4
|
1 - 3
|
2 - 6
|
0.60
- 1.67
|
Light Airs Ht 0m ~ At Sea wind makes glassy ripples on
water. On land direction of wind shown by smoke but not by wind vanes
|
|
Force 2
|
4 - 7
|
4 - 6
|
7 - 11
|
1.94
- 3.06
|
Light breeze Ht
0.1m ~ At Sea smooth wavelets On land wind felt on face; leaves rustle;
ordinary wind vane moved by wind
|
|
Force 3
|
8 - 12
|
7-10
|
13 - 19
|
3.61
- 5.28
|
Gentle breeze Ht
0.4m Slight ~ At sea slight waves no white horses. On land eaves and small
twigs in constant motion; wind extends light flag
|
|
Force 4
|
13 - 18
|
11-16
|
20 - 30
|
5.56
- 8.33
|
Moderate breeze Ht
1m - Slight to moderate ~ At Sea waves described as with occasional white
horses. On land raises dust and loose paper; small branches are moved
|
|
Force 5
|
9 - 24
|
17 - 21
|
31- 39
|
8.61 - 0.83
|
Fresh breeze Ht 2m
Moderate ~ At sea consistent white horses On land small trees in leaf begin
to sway; crested wavelets form on lakes.
|
|
Force 6
|
25 - 31
|
22 - 27
|
40 - 50
|
11.11 - 13.61
|
Strong
breeze At Sea large waves start to form,Ht 3m
Rough more extensive
white foam crests, some blown spray large branches in motion; telephone wires
whistle; umbrellas unsafe
|
|
Force 7
|
32 - 38
|
28 - 33
|
51 - 61
|
14.17
-16.94
|
Moderate (near)
gale Ht 4m Rough to very rough. At Sea waves begin to heap up and streaks
begin to appear down the waves. On land whole trees in motion; inconvenience
in walking against wind
|
|
Force 8
|
39 - 46
|
34 - 40
|
62 - 74
|
17.22
- 20.56
|
Fresh
gale Ht 5.5m Very rough to high At Sea waves get longer - crests break into
spindrift and the streaks become more pronounced, On land breaks twigs off
trees; generally impedes progress
|
|
Force 9
|
47 - 54
|
41 - 47
|
75 - 88
|
20.83 - 24.44
|
Strong
or severe gale Ht 7m High At Sea high waves and dense streaks of foam may
begin to affect visibility. On land slight structural
|
|
Force 10
|
55 - 63
|
48 - 55
|
89 - 102
|
24.72 - 28.33
|
Whole gale
or Storm - Ht 9m Very High At Sea very high waves with overhanging crests,
lots of spray makes the sea almost white, visiblility seriously affected. On
land trees uprooted considerable structural damage occurs
|
|
Force 11
|
64 - 72
|
56 - 63
|
103 to 117
|
28.61- 32.50
|
Violent
Storm Ht 11m Very High At Sea exceptionally high waves and a complete
coverage of long white foam patches. All crests blown into froth. On land
very rarely experienced; accompanied by widespread damage.
|
|
Force 12
|
73+
|
64 +
|
118 +
|
32.78+
|
Hurricane
Ht 14m plus Phenomenal At sea the air is completely filled with driving
spray, visibility extremely difficult. On land devastation occurs.
|
