| Beaufort
Force |
Speed
(mph) |
Wind
Description |
State
of Sea |
Effects
on Land |
|
0 |
Less
1 |
Calm |
Mirror-like |
Smoke
rises vertically |
|
1 |
1-3 |
Light
Air |
Ripples
look like scales; No crests of foam |
Smoke
drift shows direction of wind, but wind vanes do
not |
|
2 |
4-7 |
Light
Breeze |
Small
but pronounced wavelets; Crests do not break |
Wind
vanes move; Leaves rustle; You can feel wind on
the face |
|
3 |
8-12 |
Gentle
Breeze |
Large
Wavelets; Crests break; Glassy foam; A few whitecaps |
Leaves
and small twigs move constantly; Small, light flags
are extended |
|
4 |
13-18 |
Moderate
Breeze |
Longer
waves; Whitecaps |
Wind
lifts dust and loose paper; Small branches move |
|
5 |
19-24 |
Fresh
Breeze |
Moderate,
long waves; Many whitecaps; Some spray |
Small
trees with leaves begin to move |
|
6 |
25-31 |
Strong
Breeze |
Some
large waves; Crests of white foam; Spray |
Large
branches move; Telegraph wires whistle; Hard to
hold umbrellas |
|
7 |
32-38 |
Near
Gale |
White
foam from breaking waves blows in streaks with the
wind |
Whole
trees move; Resistance felt walking into wind |
|
8 |
39-46 |
Gale |
Waves
high and moderately long; Crests break into spin
drift, blowing foam in well marked streaks |
Twigs
and small branches break off trees; Difficult to
walk |
|
9 |
47-54 |
Strong
Gale |
High
waves with wave crests that tumble; Dense streaks
of foam in wind; Poor visibility from spray |
Slight
structural damage |
|
10 |
55-63 |
Storm |
Very
high waves with long, curling crests; Sea surface
appears white from blowing foam; Heavy tumbling
of sea; Poor visibility |
Trees
broken or uprooted; Considerable structural damage |
|
11 |
64-73 |
Violent
Storm |
Waves
high enough to hide small and medium sized ships;
Sea covered with patches of white foam; Edges of
wave crests blown into froth; Poor visibility |
Seldom
experienced inland; Considerable structural damage |
|
12 |
>74 |
Hurricane |
Sea
white with spray. Foam and spray render visibility
almost non-existent |
Widespread
damage. Very rarely experienced on land. |
