THE BEAUFORT WIND SCALE
The
effects of wind on land.
| SCALE FORCE |
WIND |
SPEED |
EFFECTS ON LAND |
| 0 |
Calm |
Less than 1 mph (1.6 km/hr) |
Smoke rises vertically |
| 1 |
Light air |
1-3 mph (1.6-4.8 km/hr) |
Direction shown by drift of smoke |
| 2 |
Light breeze |
4-7 mph (6.4-11.3 km/hr) |
Wind felt on face. Leaves rustle. Wind vane moves. |
| 3 |
Gentle breeze |
8-12 mph (12.9-19.3 km/hr) |
Leaves and twigs move. Wind extends a light flag. |
| 4 |
Moderate breeze |
13-18 mph (20.9-29 km/hr) |
Raises dust and loose paper. Moves small branches. |
| 5 |
Fresh breeze |
19-24 mph (30.6-38.6 km/hr) |
Small trees begin to sway |
| 6 |
Strong breeze |
25-31 mph (40.2-50 km/hr) |
Large branches move. Telephone wires whistle. |
| 7 |
Moderate gale |
32-38 mph (51.5-61.6 km/hr) |
Whole trees sway. Difficult to walk against wind. |
| 8 |
Fresh gale |
39-46 mph (62.8-74 km/hr) |
Twigs snap off. Walking against wind very difficult. |
| 9 |
Strong gale |
47-54 mph (75.6-86.9 km/hr) |
Direction shown by drift of smoke |
| 10 |
Whole gale |
55-63 mph (88.5-101.4 km/hr) |
Trees uprooted. Much damage to buildings. |
| 11 |
Storm |
64-72 mph (103-115.8 km/hr) |
Widespread damage. Very rare in Britain. |
| 12 |
Hurricane |
over 73 mph (over 117.5 km/hr) |
Country devastated. Enormous damage. |
The effects of wind at sea.
| SCALE FORCE |
WIND |
SPEED |
EFFECTS AT SEA |
| 1 |
Light air |
1-3 mph (1.8-5.6 km/hr) |
Small scale like wavelets on the surface. |
| 5 |
Fresh breeze |
19-24 mph (35.2-44.5 km/hr) |
White foaming crests everywhere. |
| 7 |
Moderate gale |
32-38 mph (59.3-70.4 km/hr) |
Sea heaps up. Foam blows in streaks. |
| 11 |
Storm |
64-72 mph (118.6-133.4 km/hr) |
Ships hidden in wave troughs. Air filled with spray. |
A VERSION IN WORD IS AVAILABLE ON THE SCHOOLPHYSICS CD
