Beaufort
Number |
M.P.H. |
Strength |
Wind Speed |
0 |
0-1 |
Calm |
Smoke rises vertically |
1 |
2-3 |
Light Air |
Smoke drifts slowly |
2 |
4-7 |
Light Breeze |
Leaves rustle |
3 |
8-12 |
Gentle Breeze |
Small flags fly |
4 |
13-18 |
Moderate Breeze |
Trees toss, dust flies |
5 |
19-24 |
|
Small trees sway |
6 |
25-31 |
Strong Breeze |
Large branches sway |
7 |
32-38 |
Near Gale |
Trees in motion |
8 |
39-46 |
Gale |
Twigs break |
9 |
47-54 |
Strong Gale |
Branches break |
10 |
55-63 |
Storm |
Trees snap |
11 |
64-72 |
Violent Storm |
Widespread damage |
12 |
0ver 73 |
Hurricane |
Extreme damage |
In 1806 Admiral
Sir Francis Beaufort developed a system for accurate recording
of wind speed.
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