The Beaufort Wind Scale


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

Fresh Breeze

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.