| Beaufort Scale |
Wind: km/hr
|
Speed: mph
|
Effects on Land |
Effects on Water |
0 |
below 1 |
below 1 |
Smoke rises straight up; tree leaves without perceptible motion
|
Sea flat and mirrorlike |
1 |
1 - 6 |
1 - 3 |
Rising smoke drifts; tree leaves barely move |
Ripples without foam on crests appear |
2 |
7 - 12 |
4 - 7 |
Leaves rustle slightly; wind felt on face |
Small wavelets form, with short but pronounced crests that do
not break |
3 |
13 - 19 |
8 - 12 |
Leaves and twigs move; loose paper and dust raised from ground
|
Large wavelets with breaking crests form; occasional white foam
crests |
4 |
20 - 30 |
13 -18 |
Small branches move; wind raises dust and paper |
Small waves form; white foam at crests more frequent |
5 |
31 - 39 |
19 - 24 |
Small trees sway and large branches in motion; dust clouds raised
|
Moderate waves occur, with foaming crests and possible spray
|
6 |
40 - 50 |
25 - 31 |
Large branches move continuously; wind whistles; umbrellas difficult
to use |
Large waves form, with extensive white foam crests |
7 |
51 - 62 |
32 - 38 |
Whole trees in motion; walking difficult |
Sea heaps; white foam blows in streaks from breaking waves |
8 |
63 - 74 |
39 - 46 |
Tree twigs break; walking progress slow |
Moderately high waves form, well-marked streaks of foam blow
with wind |
9 |
75 - 87 |
47 - 54 |
Slight structural damage |
High waves form, with dense streaks of foam |
10 |
88 - 102 |
55 - 63 |
Exposed trees uprooted; heavy structural damage |
Very high waves with long overhanging crests occur; great patches
of foam blows in dense white streaks |
11 |
103 - 117 |
64 - 72 |
Widespread damage |
Exceptionally high waves form; sea covered with long white patches
of foam; wave crests blown into froth |
12 |
above 118 |
above 73 |
Severe damage and destruction |
Exceptionally high waves form; air filled with foam and spray;
sea completely white |