HOW DO WE GET WIND – BASIC KNOWLEDGE FOR KITESURFERS
What is Wind? Wind is moving air.
Why is the air moving? Because of the difference in pressure.
How do we get this difference in pressure?
This is what we will be talking about in this episode. My name is Petar Pavlovic, I love sharing my kitesurfing experience with you.
Let’s talk about:
- How we get wind?
- What is the difference between High and Low pressure
- What is and how is working Thermal Wind or Sea Breeze.
HOW IS WIND CAUSED
We have High and Low pressure systems.
Low pressure system appears when the sun is heating up, let’s say the land. The land becomes hot, as the hot air is light it’s starts rising. Once the air reaches the atmosphere the air cools down. Cold air is heavier so it starts sinking towards the earth and this creates High Pressure area.
As there is air missing in the low pressure area, the air from High Pressure is replacing it and this is why and how we get wind. So the wind always blows from High to Low pressure.
HIGH AND LOW PRESSURE SYSTEM
When you are watching the windy satellite you can see that High and Low pressure are surrounded with lines. These lines are called isobars (ISO = Equal BARS = Air Pressure) which are indicating the identical pressure. The Closer the isobars are to one another stronger is the wind. High and Low pressure are meeting at 1013hpa, So 1012hpa and everything below is Low pressure system. 1014hpa and everything above is High pressure system.
In the Northern Hemisphere Hight Pressure is Turning Clockwise and Low Pressure counterclockwise. In the Southern Hemisphere the opposite is happening.
THE CORRIOLIS EFFECT
The reasons are the Pressure Belts and the Corriolis effect as the Equator is the closest to the sun so it heats up first which creates Equatorial Low pressure Belt. The air raises, it cools down and it sinks back to the earth 30* south and 30* North from the equator which creates Subtropical High Pressure belts. So as we said the wind is blowing from High to Low pressure. If the earth would not rotate the wind would blow straight. As we know that the earth is rotating, this creates the Coriolis effect. So the wind carves.
Here is another example for better understanding why the wind carves. This wind around the equator is called Trade Wind as in the past people have been using this wind for sailing across the ocean to trade animals, food and many other things. Trade wind is now known as constant wind blowing almost every day on many spots around the equator. Like in the Dominincan Republic, Cabo Verde or in Vietnam. The Equatorial Low pressure Belt is changing depending of the season. This is why some of the super windy places stay completely without wind during some months or the wind starts blowing from the opposite direction.
DIFFERENCE OF WIND IN HIGH AND LOW PRESSURE SYSTEM
- Cold air.
- Clear sky.
- Small amount of clouds can appear.
- Warm air.
- Unstable weather (Rain).
Sounds a bit strange, that it gets colder during high pressure even if it is sunny. Actually you would feel colder in the shadow or during the night. In Low pressure system you might feel really warm even if it is super cloudy and the wind is blowing. There can also be sunshine, but really quickly starts raining again.
In case there are no obstacles most often, the wind during High Pressure is more constant, The wind during Low Pressure, is unstable. During High Pressure as the wind is colder it means it’s denser so you can expect more power in your kite, it’s good wind for jumping higher. During Low Pressure the wind is warmer so less dense, sometimes it’s hard to jump super high with this kind of wind.
Example: 15knots in High Pressure feels much stronger than 15knots during Low Pressure.
I highly recommend to be watching the satellite forecast where you can see much better under what pressure system the wind is coming from so you might better understand what quality of wind to expect.
THERMAL WIND & SEA BREEZE
Thermal wind occurs exactly as normal wind, because of differences in pressure. Just this time you cannot see the difference in pressure on the forecast. Thermal wind is occurring everywhere around the world, but only in some places the wind gets strong enough to enjoy Kitesurfing. I have been kitesurfing on 3 different kite spots that are famous for kitesurfing just during thermal wind. All 3 spots had a bit different rules on how and why the wind kicks in.
The water should be cold and once the sun heats up the land, which most of the time is starting from noon. The air on the land rises and gets replaced by the air of the sea. The wind often drops during the sunset. Usually during the night there is a breeze blowing off-shore because the land cools down faster than the sea.
In all 3 spots I have been kitesurfing it was impossible for the forecast to guess the strength of the wind.
Usually in Croatia and in Montenegro, you should just watch the forecast from noon to see the good direction and if it is showing the strength of 5-10 knots, you can actually expect the wind to be around 15-20 knots.
Again this depends on the spot and what wind effects might appear, you can see more details about what wind effects you should be aware of in my previous episode.
On those 2 spots the thermal wind was mostly working just during High Pressure. If during Low Pressure it was shown a good direction of wind and again the strength of 5-10knots, there would actually be just 5-10knots of wind.
THERMAL WIND IN LEFKADA AND ON LAKES
For instance in Lefkada, Greece. It was almost impossible to guess what would happen with the wind. No matter during what Pressure System, no matter what direction of the wind the forecast was showing. If the sun was shining there was good thermal wind kicking in.
It’s also known to get good thermal wind in lakes, like Lago di Garda. Honestly I have never been kitesurfing in a lake with thermal wind, but I heard that the wind in the morning is blowing in one direction and from noon the wind completely changes direction. The direction, quality and strength of the wind again depends a lot on the surface of the land and the mountains surrounding the lake.
HOW TO APPROACH A KITE SPOT WORKING WHIT THERMAL WIND?
For any new kitesurf spot you visit I highly recommend to inform yourself about the spot with locals or with a kite school if there is one. Especially if the wind is thermal, as they might give you many useful informations on how exactly the wind on this spot works and what you have to be aware of.
I want to share with you some of my experience. In Croatia and in Montenegro, I could guess the forecast in the morning just by simply going in the sea and if I felt that the water was cold there was high chances of good thermal wind coming. If I would feel that the sea is warmer, it was almost never windy, or maybe it would be but super light.
Unfortunately In Lefkada, Greece I was not able to guess the forecast this way. You have to be aware of the clouds, especially during thermal wind, If just a small cloud appears in front of the sun, the wind could become super unstable or it can even completely kill the wind. There is also a chance that a small fluffy cloud transforms itself into a monster.