Wind Things

What is wind? It's simply the movement of air around the earth caused by the pressure differences in the air. And these differences are themselves caused by air being heated and rising, and colder air sinking and replacing the warm air (or course there is more to it than that - check out some of the weather links on the right hand side).

If you are in a perfectly flat place, with no hills, trees, or other disruptions the wind will blow consistently and 'cleanly' - i.e. there is nothing to obstruct the movement of the air. The obvious example of this is the beach where the wind will often blow in from the sea (an 'onshore' wind) and (given the general lack of mountains and other big obstructions out at sea) it will be 'clean'.

On the other hand standing in the middle of a city, surrounded by hills, about 100 miles inland, on an island (which is more or less like here in Sheffield) the wind has a lot of obstructions to contend with. Therefore the wind gets very lumpy and gusty - the result of it passing through and around all those obstructions.

Therefore beaches are the best kite flying environment (generally) and inland cities are the worst (generally). However we all have to make do with where we are and in some ways learning to fly kites in a 'poor' environment makes for better flying (and certainly more challenging) since you are always having to compensate. At least that is what we tell ourselves here.

Beaufort Scale

This scale for measuring wind was devised by Sir Francis Beaufort (but was based on earlier tables for measuring wind force) in the Royal Navy and was originally the force of wind in the canvas sails. It was changed in the later part of the century to reflect changes in shipping, and in 1939 the scales were changed to judging the winds effect on the sea surface.

MPH Beaufort Description Kiting

0 - 1 0

Calm

Sea: Mirror like sea

Land: No wind, nothing moves, smoke goes straight up, flags hang limp.

Looking at very lightweight kites - zero wind flying.

1 - 3 1

Light Air

Sea: Ripples form, but don't break.

Land: Drifting smoke - little bit of movement in flags.

Light weight kites again - but may fly without you having to move too much.

4 - 7 2

Light Breeze

Sea: Larger ripples, but still don't break.

Land: Feel the wind (just), leaves rustle on the trees, flags move more.

Most kites start to fly, but may still be an effort at the lower end - like having to walk backwards & pull on the lines to give lift. Also getting to the upper range for the light wind kites - especially if the wind is gusty.

8 - 12 3

Gentle Breeze

Sea: Little waves, begin to break on the crests.

Land: Feel the wind, small branches of trees move, flags fully extended.

Best wind range for most normal flying - just about everything will fly & the larger kites will give a good amount of power, without being silly.

13 - 18 4

Moderate Breeze

Sea: Small waves & the appearance of white horses.

Land: Light things on the ground move, small tree branches move.

Outside the range of the lighter kites and even some of the less strong kites, such as the Revolution EXP, at the 18Mph speeds.

Good for power/traction activities and fast fun with Stunt kites.

19 - 24 5

Fresh Breeze

Sea: Moderate waves, lots of white horses & a little bit of spray.

Land: Large Branches & small trees move a little bit.

Getting in the more powerful stuff - things will begin to break on kites with spars if you are not careful & you start having to know how to handle the large kites.

25 - 31 6

Strong Breeze

Sea: Large waves beginning to form & some spray.

Land: Large branches move a lot.

The upper limit for just about everything I fly - anything at this wind speed is a) going to be fast & b) powerful. You need to right kite for this wind (i.e. small) & to know what you are doing.

32 - 38 7

Moderate Gale

Sea: Form from breaking waves begins to be blown in wind's direction.

Land: Whole trees move.

Not recommended (but people do do it!) - this is where you start doing kite buggying with a postage stamp.

39-46 8

Gale

Forget it.

47-54 9

Strong Gale

Really forget it.

55-63 10

Storm

Really, really forget it!!!

64-74 11

Violent Storm

Stay at home.

>=75 12

Hurricane

Stay at home.

Links

• British Antarctic Survey - The beaufort Scale
• Met Office - The Beaufort scale