The search for the perfect wave
If it is winter on the north coast of Spain, a strange spectacle takes place: instead of beach vacationers, surfers go out into the sea. With a fixed view of the horizon, they sit on their surfboards and wait for the next big wave. The waves should be around 13 feet high but in this case, these waves are almost two to three times bigger than the average surfer.
Everything starts with the solar energy that enters the atmosphere. It heats up the equator more than the poles. The air at the equator expands as it cools and contracts at the poles. To compensate for this pressure difference, the air masses begin to move in the atmosphere. Influenced by the land masses and the climate, low pressure areas develop in the lower atmosphere. On the satellite image they can be recognized by typical turbulence of the clouds. Because the earth's rotation, the moving air is deflected in vertices.
Surfers wait anxiously for exactly these types of conditions. Because in the low-pressure areas strong winds blow near the surface of the earth and thereby right above the sea. The winds then transfer their energy to the water and bring it to a tumult. The farther the way the winds are over the water surface, the bigger the waves are. Therefore, there are hardly waves in the relatively small Mediterranean. But one hundred percent security never exists. More than three days in advance, the wave prediction is like a gamble. Too many factors affect the sea.
Tsunamis and other types of waves
Tsunamis are huge tidal waves caused by abrupt changes (movements) in the sea. A common cause are earthquakes on the seabed also known as "seaquakes". Such tidal waves can demolish entire villages, carry boats inland and kill many people. At the time of its formation, the wave begins to spread in a circle. On open sea, such waves are not noticed at all. The deeper the water, the faster a wave can spread. This can initially happen at a rate up to that of sound.
The dangerous thing about tsunamis is that the energy they receive when they are formed is passed on in the water without much loss. The entire water column, from the seabed to the surface, is set in motion. This distinguishes tsunamis from waves caused by wind or storm and which consume much less energy. When the ocean floor near the coast becomes flatter, the wave is slowed down and the wave crests rise. Water can pile up to enormous heights, in extreme cases several hundred meters. Damage is caused not only by the waves themselves, but also by water, which flows off again and again rips material with it.