How to Measure Wind Speed: The Beaufort Wind Force Scale
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Below is a wind chart, created in 1805 by Admiral Beaufort of the British Navy. Beaufort arranged the numbers 0 to 12 to indicate the strength of the wind from calm (force 0) to hurricane (force 12). Here’s a wind force scale adapted to land.
“Used Mostly at Sea but of Help to All Who Are Interested in the Weather”
Wind Force Scale
Beaufort Force |
Description |
When You See or Feel This Effect |
Wind (mph) |
Wind (km/h) |
0 |
Calm |
Smoke goes straight up |
less than 1 |
less than 2 |
1 |
Light air |
Wind direction is shown by smoke drift but not by wind vane |
1-3 |
2-5 |
2 |
Light breeze |
Wind is felt on the face; leaves rustle; wind vanes move |
4-7 |
6-11 |
3 |
Gentle breeze |
Leaves and small twigs move steadily; wind extends small flags straight out |
8-12 |
12-19 |
4 |
Moderate breeze |
Wind raises dust and loose paper; small branches move |
13-18 |
20-29 |
5 |
Fresh breeze |
Small trees sway; waves form on lakes |
19-24 |
30-39 |
6 |
Strong breeze |
Large branches move; wires whistle; umbrellas are difficult to use |
25-31 |
40-50 |
7 |
Near gale |
Whole trees are in motion; walking against the wind is difficult |
32-38 |
51-61 |
8 |
Gale |
Twigs break from trees; walking against the wind is very difficult |
39-46 |
62-74 |
9 |
Strong gale |
Buildings suffer minimal damage; roof shingles are removed |
47-54 |
75-87 |
10 |
Whole gale (Storm) |
Trees are uprooted |
55-63 |
88-101 |
11 |
Violent storm |
Widespread damage |
64-72 |
102-116 |
12 |
Hurricane |
Widespread destruction |
73+ |
117+ |
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