SM1960IM size : 110mm W x 105mm H
English
English
35
36
Beaufort Force Wind Speed
Wind Speed
Terms
Indicators
(KmPH)
(MPH)
used in
forecasts
0
0-2
0-1
Calm
Calm; smoke rises vertically.
The sea is mirror-like.
1
2-5
1-3
Light
Smoke drift indicates wind
direction.
2
6-12
4-7
Light
Wind felt on face, leaves rustle.
3
13-20
8-12
Gentle
Leaves and small twigs in
constant motion.
4
21-29
13-18
Moderate
Raises dust, leaves and loose
paper; small branches move.
At sea, small waves 1-4ft
(up to 1.2m) take form.
5
30-39
19-24
Fresh
Small trees in leaf begin to
sway; crested wavelets form
on inland waters. At sea, 4-8ft
(1 to 2.5m) waves.
6
40-50
25-31
Strong
Large branches in motion;
whistling heard in wires;
umbrellas used with difficulty.
At sea, 8-13ft (2.5-4m) waves.
7
51-61
32-38
Strong
Whole trees in motion;
inconvenience felt while
walking against the wind.
At sea, 13-20ft (4-6m) waves.
8
62-74
39-46
Gale
Breaks twigs off trees;
generally impedes progress.
9
75-87
47-54
Gale
Slight structural damage,
roofing dislodged, larger
branched break off. High waves
(20ft/6m), reduced visibility at
sea.
10
88-101
55-63
Storm
Seldom experienced inland;
trees uprooted; considerable
structural damage occurs.
At sea, 20-30ft (6-9m) waves.
11
102-116
64-72
Storm
Very rarely experienced inland;
accompanied by widespread
damage. Exceptionally high
waves 30-45ft (9-14m).
12
117 or more
73 or more
Hurricane
Very rarely experienced;
accompanied by widespread
damage. At sea, waves over
45ft/14m, visibility greatly
reduced.
