Beaufort
Force |
Wind Speed
(KmPH)
|
Wind Speed
(MPH)
|
Indicators
|
Terms Used in NWS Forecasts
|
| 0 |
0-2 |
0-1 |
Calm; smoke rises vertically. |
Calm |
| 1 |
2-5 |
1-3 |
Shown by direction of wind smoke drift, but not by wind vanes.
|
Light |
| 2 |
6-12 |
4-7 |
Wind felt on face, leaves rustle; ordinary vanes moved by wind. |
Light |
| 3 |
13-20 |
8-12 |
Leaves and small twigs in constant motion; wind extends light
flag. |
Gentle |
| 4 |
21-29 |
13-18 |
Raises dust and loose paper; small branches are moved. |
Moderate |
| 5 |
30-39 |
19-24 |
Small trees in leaf begin to sway;
crested wavelets form on inland waters. |
Fresh |
| 6 |
40-50 |
25-31 |
Large branches in motion; whistling heard
in telephone wires; umbrellas used with difficulty. |
Strong |
| 7 |
51-61 |
32-38 |
Whole trees in motion; inconvenience felt
walking against the wind. |
Strong |
| 8 |
62-74 |
39-46 |
Breaks twigs off trees; generally impedes
progress. |
Gale |
| 9 |
75-87 |
47-54 |
Slight structural damage. |
Gale |
| 10 |
88-101 |
55-63 |
Seldom experienced inland; trees uprooted; considerable structural damage occurs. |
Whole gale |
| 11 |
102-116 |
64-72 |
Very rarely experienced inland; accompanied by widespread damage. |
Whole gale |
| 12 |
117 or more |
73 or more |
Very rarely experienced; accompanied by widespread damage. |
Hurricane |
