WIND

WIND                 

 

On our planet we observe a natural movement of air masses due mainly to the rotation of the earth, to the differences in temperature and pressure. Air is a fluid; as water flows from the top of the mountains towards the plains, the air tends to “descend” from the anticyclones (areas of high pressure) towards the depressions (areas of low pressure). Wind is a horizontal displacement of air, generated by the pressure force which tends to move the atmosphere from areas of high pressure to areas of low pressure to achieve uniform pressure. It is therefore a rebalancing phenomenon. The wind is driven by temperature gradients:

Warm air, less dense, weighs less than cold air. It therefore tends to rise. This phenomenon is called convection. This is a vertical air flow: in contact with the soil, air to become warm, it becomes lighter and rises; then there is an ancestry. With increasing altitude, the air expands as the air pressure decreases, and cools. The lift ends when the air temperature reaches that of the surrounding environment. Conversely, air colder than the ambient air will tend to descend, to compress and to heat up. The heating of the air at the start as well as its hygrometry determine the extent of the movement. Indeed, the temperature of dry air decreases by 1 ° C every 100m while that of air saturated with water decreases by 0.5 ° C for the same distance.

We use an anemometer to know the precise speed of the wind and we estimate it using the Beaufort scale.

 

Vertical air movements are used in paragliding, gliding ( glider). Horizontal air movements are used by windsurfing and kit and sailing sports.

All of these sports benefit from the beneficial effect of the air current .

 

But the object of this talk is   precisely the 'evil' effects of this moving air. If the wind has been used for thousands of years to move (sailboats) or to create energy (windmill, wind turbine), it remains the number one enemy of the cyclist, much more than the rain. . Roll by strong wind is never much fun ... except when he was in the back ...

 

 

Steegmans struggled with the wind during Gand-Wevelgem 2015 ...

( Wind 90km / h)

 

 

 

Another perilous exercise to ride with an open umbrella ! ...

 

 

 

Riding a bicycle in strong winds is a perilous exercise that should not be recommended for novices.

 

Choosing a good bike :

Avoid profiled gentes (lenticular wheels) and the frame with wide tubes which offers good grip in the winds

Force yourself out when it's blowing to learn

Plan a short outing

Give up if the wind is stormy

When the wind blows too hard, not only will you have no fun, it's dangerous : you risk ending up on the ground, or worse, in a car. Choose a safer sport (mountain biking, running, Nordic walking)

Make yourself " small " 

Put on tight clothes. No way the K-Way turns into a spinnaker or parachute

When the wind comes from the face

Ride with your hands off the handlebars, tuck your elbows in and lower yourself as much as possible

When the wind comes from the side

You have to lean against the wind : lean on the side where the wind comes from so that it does not deport you or unbalance you .

But beware of irregular winds : anticipate to recover in time if the wind weakens.

If the wind is blowing from the left, do not ride too close to the side of the road, allow yourself a safety step, otherwise a squall could send you into the background

The wind descending

Downhill, crosswinds and gusts on bends are the most dangerous, but tailwinds can also be tricky. So be careful!

Do not wear your windbreaker if it is loose (and if the cold is bearable), to minimize wind

resistance Put on the large chainring and pedal non-stop (except in the bends, of course). This will have the effect of "breaking" the wind grip a little and you will stabilize your bike better.

Brake at the same time to reduce your speed

Let your friends go, they will be waiting for you downstairs! Better to arrive slowly on the bike than on a stretcher

Stay flexible with the arms to be able to anticipate, especially in the bends of a pass, where the gusts are sometimes unpredictable.

 

Crossing a high bridge

Crossing a bridge can be difficult. I am thinking in particular of certain bridges over the Rhône when the mistral is blowing in force.

If the bridge barrier is perforated, watch out for thrusts (increasingly stronger towards the middle of the bridge), which can throw you against a car. In the worst case, cross the bridge on foot.

 

Reading the wind in the landscape

Learn to anticipate squalls by observing the surroundings : A cornfield, a hedge, an embankment will temporarily shelter you .

But by the time you're out in the open again, you're going to get a blast . So get ready to “lean” against the wind!

Observe the vegetation , spot the trees and bushes in the distance.

In the villages , the wind swirls and can come from any direction: observe everything that moves in the wind, even the dust on the road…

In the winding pass roads , often the wind changes direction in a rhythmic way: a portion of the face, a portion of the back.

Save the diagram to be able to anticipate and observe the vegetation well: the grass lying down, over there on the rock, is not a good sign!