Waves, their beauty, continuous movement and variability never cease to amaze a person.
It is important to understand that changes in the ocean occur every second, the waves in it are infinitely different and unique.
Successful surfing is impossible without understanding how waves appear and propagate, which changes their speed, strength, shape, height.
Let's first understand the terminology.
wave anatomy
The periodic oscillation of the waters about the equilibrium position is called a wave.
She has the following elements:
- sole- lower plane;
- crest(linden, from English lip - lip);
- front- crest line;
- pipe(tube/barrel) - the area where the ridge meets the sole;
- wall(wall) - the sloping part on which the surfer slides;
- shoulder- the area where the wall becomes flat;
- peak is the point of incidence of the wave;
- impact zone- a place where linden falls.
Due to the variability of the waves, it is extremely difficult to measure them. Fluctuations are evaluated by several parameters.
Height- the distance from the sole to the ridge. They measure it differently. In reports for surfers indicate the difference in the oscillation of weather buoys. Sometimes the height of the wave is indicated in " growth».
Since the athlete glides along the wave, bending over, 1 "height" is approximately 1.5 meters.
Length is the distance between adjacent ridges.
steepness is the ratio of height to wavelength.
Period– time between two waves in a group (set).
Causes and features of wave formation
Contrary to naive ideas, a sea or ocean wave is not formed from coastal winds. The most common waves form far out in the ocean.
The wind, blowing in one direction for a long time, shakes huge masses of water, sometimes the size of a multi-storey building. Large winds are formed in the zone of extremely low pressure, characteristic of an anticyclone.
In moderate winds, the surface of the ocean appears steep short waves- "sheep".
At the inception stage 2D waves, whose height does not exceed the length, run in parallel elongated rows of ridges. As the wind increases, the crests disappear, and the wavelength grows faster.
When the wave and wind speeds equalize, the growth of the crests stops. From that moment on, the speed, length and period of the waves increase, and their height and steepness decrease. Such long waves more suitable for.
With a growing storm, younger waves overlap older ones, the sea seems to be erratic. When it reaches a peak, the waves become as long as possible, with extended fronts. Wherein the length of the ridges can increase to hundreds of meters(record - up to 1 km).
Waves whose crest is several times the wavelength are called three-dimensional. Most often, three-dimensional waves consist of alternating "hills", "bumps" and "troughs". Waves come in sets (groups) of 2–10. Most often, 3. Usually medium wave- the highest and correct in the set.
What moves the wind
Any new wave raises, then lowers the water masses.
Interesting fact: water particles do not move horizontally, but in an irregularly shaped circle or ellipse perpendicular to the wave front.
In fact, the trajectory of the movement of water particles resembles loops: the intensive rotation of the "water wheel" is superimposed by a weak forward movement towards the wind.
This is how the profile of the wave is formed: its windward slope is gentle, and the leeward slope is steep.
Because of this, the ridges collapse, forming foam.
It is not the mass of water that moves during the wind, but the profile of the wave. So, lost by the surfer will swing back and forth, up and down, slowly moving towards the shore.
What sets the wave parameters
They depend on the speed, duration of the wind, changes in its direction; from the depth of the reservoir, the length of the wave acceleration.
Last determined by the size of the water area.
The action of the wind should be enough to cover the entire space.
That's why stable waves for are usually found on the ocean coast.
Changes in wind speed and direction more than 45 degrees, the old oscillations slow down, then a new wave system is formed.
Swells
Having reached the maximum size, the waves set off on a journey to the shores. They align: smaller ones are absorbed by large ones, slow ones are absorbed by fast ones.
An array of waves of the same size and power generated by a storm is called swell. The path of a swell to the coast can last thousands of kilometers.
Distinguish wind And bottom swells.
- First not suitable for surfing: in it the waves will not travel a long distance and will break already at great depths.
- Second- what you need, its long fast waves will go a long way and will be steeper when breaking.
Swells differ in amplitude and period. More period - better and smoother waves.
In Bali, waves with a period of less than 11 seconds are called wind swells. From 16 seconds - excellent waves, a period of 18 seconds - good luck, which surfers flock to catch.
For every spot the optimal direction of the swell is known, at which high-quality waves are formed.
Waves crashing
Moving towards the shore, while bumping into shallows, reefs, islands, the waves gradually waste their former power.
The longer the distance away from the center of the storm, the weaker they are.
When meeting with shallow water, rolling water masses have nowhere to go, they move up.
The period of the waves decreases, they seem to shrink, slow down, become shorter and steeper. This is how the surf wave grows.
Finally, the crests capsize, breaking or breaking the waves. The greater the depth difference, the steeper and higher the wave will be!
It occurs near reefs, rocks, shipwrecks, on a steep sandbar.
Ridge growth begins at a depth equal to half the height of the wave.
Wind directions
rise at dawn to
ride in calm water on smooth water - it's the perfect setting.
The quality of the waves depends on the coastal wind, some of the highest quality -.
- Onshore- Wind blowing from the ocean.
- offshore– wind from the shore towards the ocean.
- Crossshore- wind along the shore.
He "blows off" the crests, crushes the waves, as a result they become tuberculate; doesn't let them get up.
Onshore forces the waves to close ahead of time. This worst for surf wind, it can ruin the whole skating.
It is dangerous when the directions of the wind and the swell coincide.
If he does not fly in gusts, then he gives the waves the correct shape, “raises” them and pushes back the moment of collapse.
It's the wind perfect for surfing.
It does not improve sometimes spoils a lot wave front.
Wave types
closeout- a closed wave that breaks immediately along its entire length, therefore unsuitable for skiing.
gentle waves do not differ in speed and steepness. With a slight slope of the bottom, they break slowly without forming a high wall and pipe, therefore recommended for beginners.
Plunging waves- powerful, fast, high waves that occur with a sharp drop in depth. Create opportunities for tricks. They form inside the cavity - pipes that allow you to make passages inside.
Preferred for professionals, are dangerous for beginners - they fall more often.
Types of surf spots
The place where the wave rises is called surf spot. The nature of the wave is determined by the features of the seabed.
- Beach break- a place where the waves break on the sandy bottom. In a section with different depths, the wave bends and collapses towards the shallows. This creates an opportunity for the surfer to glide across the water wall.
Video
Watch a video about the conquest of a giant wave by a surfer:
What causes the appearance of most waves in the oceans and seas, about the destructive energy of the waves and about the most gigantic waves, and the largest tsunamis that man has ever seen.
The highest wave
Most often, waves are generated by wind: air moves the surface layers of the water column at a certain speed. Some waves can accelerate up to 95 km / h, while the wave can be up to 300 meters long, such waves travel huge distances across the ocean, but most often their kinetic energy is extinguished, consumed even before they reach land. If the wind subsides, then the waves become smaller and smoother.The formation of waves in the ocean is subject to certain patterns.
The height and length of the wave depends on the speed of the wind, on the duration of its impact, on the area covered by the wind. There is a correspondence: the highest wave height is one seventh of its length. For example, a strong breeze generates waves up to 3 meters high, an extensive hurricane - up to 20 meters on average. And these are already truly monstrous waves, with roaring foam caps and other special effects.
The highest ordinary wave of 34 meters was noted on the territory of the Agulhas Current (South Africa) in 1933 by sailors from the American ship Ramapo. Waves of this height are called "killer waves": in the gaps between them, even a large ship can easily get lost and die.
In theory, the height of normal waves can reach 60 meters, but these have not yet been recorded in practice.
In addition to the usual wind origin, there are other mechanisms of wave formation. The cause and epicenter of the birth of a wave can be an earthquake, a volcanic eruption, a sharp change in the coastline (landslides), human activity (for example, testing a nuclear weapon) and even a fall into the ocean of large celestial bodies - meteorites.
The biggest wave
This is a tsunami - a serial wave that is caused by some kind of powerful impulse. A feature of tsunami waves is that they are quite long, the distance between crests can reach tens of kilometers. Therefore, in the open ocean, a tsunami does not pose a particular danger, since the height of the waves is on average no more than a few centimeters, in record cases - a meter and a half, but the speed of their propagation is simply unthinkable, up to 800 km / h. From a ship on the high seas, they are not noticeable at all. The tsunami acquires destructive power when approaching the coast: reflection from the coast leads to compression of the wavelength, but the energy does not go anywhere. Accordingly, its (wave) amplitude, that is, the height, increases. It is easy to conclude that such waves can reach much higher heights than wind waves. 
The most terrible tsunamis occur due to significant disturbances in the relief of the seabed, for example, tectonic faults or shifts, due to which billions of tons of water begin to abruptly move tens of thousands of kilometers at the speed of a jet aircraft. Catastrophes occur when all this mass slows down on the shore, and its colossal energy first goes to increase the height, and eventually falls on land with all its might, a water wall.
The most "tsunami-prone" places are bays with high banks. These are real tsunami traps. And the worst thing is that a tsunami almost always comes suddenly: in appearance, the situation at sea can be indistinguishable from an ebb or flow, an ordinary storm, people do not have time or even think to evacuate, and suddenly they are overtaken by a giant wave. The warning system is little developed.
Territories with increased seismic activity are areas of special risk in our time. No wonder the name of this natural phenomenon is of Japanese origin.
The worst tsunami in Japan
The islands are regularly attacked by waves of various calibers, and among them there are truly gigantic, entailing human casualties. An earthquake off the east coast of Honshu in 2011 triggered a tsunami with a wave height of up to 40 meters. The earthquake is rated as the strongest in the recorded history of Japan. The waves hit the entire coast, together with the earthquake, they claimed the lives of more than 15 thousand people, many thousands went missing. 
Another highest wave in the history of Japan hit the west of Hokkaido in 1741 as a result of a volcanic eruption, its height is estimated at 90 meters.
The biggest tsunami in the world
In 2004, on the islands of Sumatra and Java, the tsunami caused by a strong earthquake in the Indian Ocean turned into a massive disaster. Died, according to various sources, from 200 to 300 thousand people - a third of a million victims! To date, it is this tsunami that is considered the most destructive in history. 
And the record holder for the wave height is named "Lutoya". This tsunami, which swept through Lituya Bay in Alaska in 1958 at a speed of 160 km / h, was triggered by a giant landslide. The wave height was estimated at 524 meters.
Meanwhile, the sea is not always dangerous. There are "friendly" seas. For example, no river flows into the Red Sea, but it is the cleanest in the world. .
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Giant waves are called "tsunamis". They are of enormous height and width, arising in the ocean under the influence of water (most often due to earthquakes). The word itself comes from the Japanese language, where it consists of two hieroglyphs - “wave” and “bay”. It was Japan and other countries with access to the Pacific Ocean that became victims of killer waves. In the Pacific region, a wave in the world was witnessed, which hit the coast of American Alaska.
Top 1. Tsunami in Lituya Bay, 1958
Lituya Bay is located in the northeastern part of the Gulf of Alaska. The bay is separated from the outlet to the ocean by a strait about 500 meters wide. Lituya Bay is about 11 kilometers long and about 3 kilometers wide. Cenotaph Island is located in the center of the bay.
The catastrophe was provoked by the earthquake that took place on July 9, 1958. It caused a rockfall on the Gilbert Glacier northeast of the bay. About 30 million cubic meters of rock and ice fell into the eastern part of the bay from a height of about 900 meters. The tsunami caused by the rockfall hit both sides of the bay and Cenotaph Island. The La Gaussy spit, located near the epicenter of the wave, was washed away almost completely. The wave height was 524 meters. The tsunami uprooted most of the trees in the passage area.
Five people became victims of a huge wave. Two of them were caught by the tsunami on a fishing boat. The people who went out into the bay on that fateful day on two more ships miraculously survived and were picked up by rescuers.
Top 2. Indian Ocean, 2004
The 2004 tsunami went down in history as the deadliest - more than 230 thousand people became victims of the wrath of nature. The beginning of a giant wave was laid by an underwater earthquake with a magnitude of 9 points. The tsunami waves that hit the land reached a height of thirty meters.
Radar satellites recorded an underwater tsunami, whose height after the earthquake was about 60 centimeters. Unfortunately, these observations could not help prevent a catastrophe, because it took several hours to process the data.
Sea waves reached the coast of different countries at different times. The first blow immediately after the earthquake hit the north of the island of Sumatra. The tsunami reached Sri Lanka and India only an hour and a half later. Two hours later, the waves hit the shores of Thailand.
Tsunami waves led to human casualties in the countries of East Africa: Somalia, Kenya, Tanzania. Sixteen hours later, the waves reached the town of Struisbaa on the coast of South Africa. A little later, tidal waves up to a meter high were recorded in the area of the Japanese scientific station in Antarctica.
Part of the tsunami energy escaped into the Pacific Ocean, where tidal waves were recorded on the coast of Canada, British Columbia, and Mexico. In some places, their height reached 2.5 meters, which exceeded the waves recorded off the coast of some countries located closer to the epicenter.
The most affected by the tsunami were:
- Indonesia. Three waves hit the northern part of the island of Sumatra less than half an hour after the earthquake. According to survivors, the waves were taller than houses.
- Andaman and Nicobar Islands (India), where more than 4 thousand people died.
- Sri Lanka. The waves reached a height of 12 meters. The passenger train "Queen of the Sea Coast" became a victim of the tsunami. His death was the largest railway accident in recent history and claimed more than 1,700 lives.
- Thailand. Waves second only to those that hit Sumatra destroyed the southwestern coast of the country. There were many tourists from other countries at the scene of the tragedy. More than 3,000 people died and 5,000 more went missing.
Top 3. Japan, 2011
In March 2011, an underwater earthquake hit the ocean east of Honshu. It provoked a tsunami wave that devastated the coast of Honshu and other islands of the archipelago. The waves reached the opposite shore of the Pacific Ocean. In the coastal regions of South American countries, an evacuation was announced, but the waves did not pose a big threat.
The waves reached the islands of the Kuril chain. Several thousand Russian citizens were evacuated from the coastal areas of the islands by the Ministry of Emergency Situations. Waves up to three meters high were recorded near the village of Malokurilskoye.
The first tsunami waves hit the Japanese archipelago within half an hour after completion. The highest height was witnessed near the city of Miyako (northern Honshu) - 40 meters. The coast received the heaviest blows within an hour after the earthquake.
The tsunami caused damage to three Japanese prefectures in Honshu. Also, the cataclysm provoked an accident at a nuclear power plant. The city of Rikuzentakata was actually washed into the ocean - almost all the buildings went under water. The tragedy of 2011 claimed the lives of more than 15 thousand inhabitants of the Japanese archipelago.
Probably, the sparseness of the state of Alaska was the reason why the largest wave in the world did not lead to massive loss of life. Today, the earthquake and tsunami monitoring system has been improved, which makes it possible to reduce the number of victims during disasters. But coastal residents are still at risk due to the unpredictable behavior of the ocean.
Monster waves, white waves, killer waves, rogue waves - all this is the name of one terrible phenomenon that can take a ship by surprise. TravelAsk will talk about the biggest waves in the world.
What is the peculiarity of giant waves
Killer waves are fundamentally different from tsunamis (and we will also tell you about the biggest tsunamis). The latter come into action as a result of natural geographical disasters: earthquakes or landslides. A giant wave appears suddenly, and nothing portends it.
Moreover, they were considered fiction for a long time. Mathematicians even tried to calculate their height and peculiarity of dynamics. However, the cause of the giant waves has not been established.
First recorded giant wave
For the first time, such an anomaly was recorded on January 1, 1995 on the Dropner oil platform in the North Sea off the coast of Norway. The height of the wave reached 25.6 meters, and they called it the Dropner wave. In the future, space satellites were used to conduct research. And within three weeks, another 25 giant waves were recorded. In theory, such waves can reach 60 meters.
The highest killer waves in history
The most gigantic wave in history was noted on the territory of the Agulhas Current (South Africa) in 1933 by sailors from the American ship Ramapo. Its height was 34 meters.
In the mid-Atlantic, the Italian transatlantic liner Michelangelo was hit by a killer wave in April 1966. As a result, two people were washed out to sea, and 50 were injured. The ship itself was also damaged.
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In September 1995, the Queen Elizabeth 2 liner recorded a 29-meter rogue wave in the North Atlantic. However, the British transatlantic ship turned out to be not one of the timid: the ship tried to "saddle" the giant, which appeared right on the course.
In 1980, a meeting with a white wave ended in tragedy for the English cargo ship Derbyshire. The wave broke through the main cargo hatch and flooded the hold. 44 people died. It happened off the coast of Japan, the ship sank.
On February 15, 1982, in the North Atlantic, a huge wave covered a drilling platform owned by Mobil Oil. She broke the windows and flooded the control room. As a result, the platform capsized, killing 84 crew members. This is a sad record for today in the number of deaths from a killer wave.
In 2000, the British cruise ship Oriana was hit by a 21-meter wave in the North Atlantic. Before that, a distress signal was received on the liner from a yacht that was damaged due to the same wave.
In 2001, all in the same North Atlantic, a giant wave hit the luxury tourist liner Bremen. As a result, a window on the bridge was broken, because of this, the ship was drifting for two hours.
Dangers on the lakes
Rogue waves can also appear on lakes. So, on one of the Great Lakes, the Upper, the Three Sisters meet - these are three giant waves that follow each other. The ancient Indian tribes who lived in this territory also knew about them. True, according to legend, the waves appeared due to the movement of a giant sturgeon that lived at the bottom. The sturgeon has never been discovered, but the Three Sisters appear here and now. In 1975, the Edmund Fitzgerald cargo ship, which was 222 meters long, sank precisely because of a collision with these waves.
