Spark image

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
 
 
 
© Keith Gibbs 2020