Do you know the winds?

Knowing the winds and currents is an important skill for seafarers. Winds at sea affect the speed of navigation, the direction of navigation and, of course, weather conditions. Knowing the direction, strength and nature of the winds, and anticipating weather conditions, is essential to ensure safe navigation.

Why does the wind blow?

The sun warms land and sea all the time, although unevenly. This means that some parts of the Earth are warming more, while others are warming less. As the surface radiates heat energy, the air above the surface warms. Warm air has a lower density and becomes lighter than cold air.  As it becomes lighter, it starts to rise and cooler air starts to flow in its place. This movement of air is felt as wind.

 

 

Wind is therefore the phenomenon of air moving from an area of higher air pressure towards an area of lower air pressure. The greater the difference between high and low air pressure, the stronger the wind. Wind speed is often also influenced by the shape of the land surface, such as hills, narrow valleys, etc.

Wind is measured using a variety of instruments that allow wind speed and direction to be accurately determined.

 

Wind speed is the distance the wind covers in a given time. It is mostly measured in kilometres per hour (km/h). In nautical terms, however, the units used are knots or nautical miles per hour (nmi/h). A device for measuring wind speed and direction is called an anemometer. Wind direction is reported in degrees and can be described by the direction of the sky.

 

 

 

The Beaufort scale is also used to measure wind strength. The scale was introduced in 1805 by British Admiral Francis Beaufort. The scale consists of 17 grades and also describes the state of the sea and the waves.

 

Due to geographical, climatic, and seasonal factors, there are many different types of winds around the world. Some of these winds are very specific to certain areas. 

In the Adriatic Sea, the following winds are known:

 

 

Tramontana is a transitional wind, blowing from the north. It can start blowing suddenly and can reach up to 200 km/h.

 

Maestral is a summer wind that blows from the sea towards the land from a north-westerly direction. It usually starts after 9 am and stops before sunset. It brings steady, warm weather. Although it does not reach high strength it can be very uncomfortable for small boats.

 

Burja (or Bora) is a cold, dry wind blowing from the northeast, bringing clear, sunny weather. It is characterized by gusty winds and is dangerous mainly owing to its rapid formation and rapid development, which has caused many accidents at sea. It descends obliquely into the sea along steep and high coasts, causing rough seas and breaking waves.  The strength of the storm weakens as we move away from the shore. Storms can last for weeks in winter and just for an hour in summer.

 

Yugo is a warm, moist wind that develops over a long period and reaches its maximum strength after a few days. It blows from the south-east. It brings changeable weather, most often with precipitation. Although it blows steadily, it can stir up the sea. It is signalled by hazy south-easterly horizon and sometimes high tides. In winter, it can blow intermittently for up to three weeks.

 

Levant is a short-lived, cold and moist wind that blows from the east and occurs mainly in winter. It usually turns into a southerly or gale.

 

Ponent is a short-lived wind blowing from a westerly direction and can occur at any time of the year. It is most common in cold weather but can be very strong and cause high waves. It is dangerous because of its rapid onset... 

 

Lebič is a stormy southwesterly wind that causes large waves and rough seas. A foggy band on the southwest horizon is a sign that the wind is approaching.

 

Oštro is a short-lived, very strong wind blowing from the south. It is sometimes the harbinger of a storm.