WIND SCALE
In 1806 Admiral Sir Francis Beaufort of the British Navy devised a wind velocity scale to enable the captains of sailing ships to accurately assess wind speeds at sea. Though the original scale dealt with purely maritime effects, it has since been modified for land by the National Weather Service.Force |
M.P.H |
Wind |
Descriptions |
|
 |
0 | Less then 1 | Calm | Smoke rises vertically. |
 |
1 | 1-3 | Light air | Direction of wind shown by smoke drift. |
 |
2 | 4-7 | Light breeze | Wind felt on face, leaves rustle. |
 |
3 | 8-12 | Gentle breeze | Leaves and small twigs in constant motion, wind extends flag. |
 |
4 | 13-18 | Moderate breeze | Wind raises dust and loose paper, small branches move. |
 |
5 | 19-24 | Fresh breeze | Small trees in leaf start to sway. |
 |
6 | 25-31 | Strong breeze | Large branches in motion, umbrellas used with difficulty. |
 |
7 | 32-38 | Near gale | Whole trees in motion, inconvenient to walk against wind. |
 |
8 | 39-47 | Gale | Twigs break from trees, difficult to walk. |
 |
9 | 48-54 | Strong gale | Slight structural damage occurs, slates removed. |
 |
10 | 55-63 | Storm | Trees uprooted, considerable structural damage. |
 |
11 | 64-72 | Violent storm | Widespread damage. |
 |
12 | Greater then 72 | Hurricane | Widespread severe damage. |