A rogue wave is a dangerous wave type that’s usually unpredictable and abnormally large. You may have heard people or experts refer to them as king waves, abnormal waves, extreme waves, sleeper waves, monster waves, freak waves, sneaker waves, killer waves, or episodic waves.
Scientists only started believing the sightings of king waves in the past few decades. Until then, it was considered an impossible occurrence scientifically. Abnormal waves are called extreme storm waves by those who study them. They’re significantly bigger than normal waves. In addition, they’re not the same as tsunamis which are caused by landslides or earthquakes and move till they reach the shore.
This article is all you need to learn about the basics of extreme waves, including their formation and prediction. There are many facts to discover in this special guide that ocean, boating, swimming, and surfing aficionados will find worth knowing!
Normal Wave Description
You first have to know the characteristics of normal waves so that you can better understand how rogue waves are different from them. As you read the defined attributes of regular waves below, keep the waves that you’re used to in mind, like the ones surfers ride.
- Crest: A wave’s highest part.
- Trough: A wave’s lowest part, which is also referred to as the “dip” between two waves.
- Wave Height: The distance from the crest to the trough.
- Wave Length: The distance between two crests (the crests of two waves).
- Wave Speed/Period: The amount of time that it takes for the next crest to appear.
- Wave Energy: The amount of potential and kinetic energy held by a wave.
Many factors affect the above-mentioned characteristics. For example, tidal forces, ocean depth, wind, stationary structures (e.g., islands), etc. Keep in mind that a great number of waves move and meet one another at any point in time. Also, the faster and longer the wind, the stronger and bigger the wave.
Note: A fetch is a stretch of ocean across which wind can blow without hindrance. The more the fetch the greater the waves.
Rogue Wave Description
Rogue waves have been described as being larger than two times the size of their neighboring (normal) waves. They’re also known to appear suddenly without warning from the most unlikely directions due to the present wind and wave movement.
Several observers have reported that this phenomenon looks like a wall of water and may have a steep-sided form with uncommonly deep troughs. The height of a rogue wave can sometimes be close to 100 feet (around 30 meters).
It’s difficult to properly measure and analyze these wave types because of how rare and unpredictable they are. Their formation process is still in question. However, scientists have been able to uncover some factors that may come into play, as explained in the next section.
Rogue Wave Formation
The following are a couple of causes of rogue waves that have been determined by experts:
Storm Wave Energy Concentration
Waves formed by storms may build up in a water current and flow in the opposite direction of other waves. This means that the former will clash against the latter, thereby decreasing the wave frequency and forcing the waves to keep combining until a monster wave is produced.
For example, a 7-meter wave passing over a 12-meter one might yield a wave that’s as high as 19 meters. The reverse can also be the case when an 18-meter wave going across a 7-meter trough brings about a wave that’s around 11 meters high.
It just takes many waves coming together at the perfect moment(s) for a giant wave to be produced. For example, nine 7-meter waves joining together can lead to a roughly 64-meter king wave.
Powerful storms can create longer wave heights of up to 15 meters (50 feet). Such waves can increase in height and break when they go against a strong current. Freak waves that manifest this way typically last longer.
Factors that lead to the focusing of wave energy are known to come into play in the Agulhas Current of the southwest Indian Ocean and the Gulf Stream of the Gulf of Mexico.
Constructive Interference of Swells
Killer waves can also manifest due to swells that travel across oceans. A swell is a series or succession of large mechanical or surface gravity waves brought about by faraway weather systems. They’re also described as crestless wind waves that feature a small range of long wavelengths.
Swells move at various speeds and in different directions which leads them to meet one another. The clashes may bring about their merging to become greater in size. The result of many bigger swells joining together will be a very tall wave that disappears fast. Although swells that unite while moving in the same direction may last longer,
Note: As stated earlier, gales (strong winds) may also influence the formation of rogue waves, but this event can also happen in comparatively calm oceans. Also, not all extreme abnormal waves take place in oceans. It may occur in other water bodies like lakes.
Rogue Wave Prediction
The frequency of rogue waves remains a mystery, but recent studies have shown that they may not be totally unpredictable or need a storm to be developed. MIT researchers have been able to create an algorithm that will warn of the direction a rogue wave might rise from and its timing with a two-minute or three-minute head start.
The device analyses data from surrounding waves based on wave group height and length. It also calculates probabilities for potential giant waves within a few minutes.
Among all the tales of the sea (confirmed and mythical), none is as daunting to the most daring sailors, surfers, and long-distance swimmers as the rogue wave. It's a phenomenon that creates feelings of strong dislike for ocean exploration.
So be ready for the danger that may be brewing to strike at any moment while at sea. And of course, it shouldn’t be surprising to see it disappear without a trace in a couple of seconds.