We can describe the wind by talking about its strength or speed and the direction in which it is blowing. This lesson explains about how to monitor wind Speed Direction and Strength and the weather instruments to measure wind Speed Direction and Strength.
Examples of weather instruments
E.g. – * North wind blows from the North towards the South.
* South wind blows from the South towards the North.
The wind sock is a long cloth tube through which the wind is funneled.
It shows both the direction and strength of the wind.
E.g. – The straighter the sock, the stronger the wind.
The winds that almost always blow from the same direction are called prevailing winds.
The westerlies or westerly winds are the most frequent prevailing winds in Britain.
These move across the Atlantic Ocean bringing windy, wet weather to the high mountains and moorlands in the west. Land east of these areas is drier.
An Anemometer is the scientific instrument for measuring wind speed. It comes with four little cups attached by a shaft, to a meter or to a scale. The four little cups turn in the wind. When the wind blows harder, the cups of the anemometer turn faster and that is the higher reading on the meter.
We can estimate the speed of the wind by seeing what effect it has on smoke, flags and tree branches.
This is a scale used to measure the strength of the wind. The Beaufort scale is a system of recording wind strength invented in 1805 by Sir Francis Beaufort. It is a numerical scale ranging from 0 for calm to 12 for a hurricane. Sailors and forecasters use the Beaufort Wind Scale as a standardized way to rate wind strength.
Effects on land
| Smoke rises straight up; tree leaves without perceptible motion|
1 – 6
| Rising smoke drifts; tree leaves barely move|
7 – 12
| Leaves rustle slightly; wind felt on face|
13 – 19
| Leaves and twigs move; loose paper and dust raised from ground|
20 – 30
| Small branches move; wind raises dust and paper|
31 – 39
| Small trees sway and large branches in motion; dust clouds raised|
40 – 50
| Large branches move continuously; wind whistles; umbrellas difficult to use|
51 – 62
| Whole trees in motion; walking difficult|
63 – 74
| Tree twigs break; walking progress slow|
75 – 87
| Slight structural damage|
88 – 102
| Exposed trees uprooted; heavy structural damage|
103 – 117
| Widespread damage|
| Severe damage and destruction|
Also, read the lesson Wind Facts Wind Formation Wind Classification.