How Are Waves Formed? (& Best Type of Wave for Surfing)

As someone who has a love for surfing, your favorite pastime greatly relies on the waves of the ocean.

With no waves or the incorrect type of waves, you simply will not be able to surf.

So, How Are Waves Formed?

Ocean waves are formed by wind friction on the surface of the ocean (wind swell), through gravitational pulls from the sun and moon (tidal waves), as well as disturbances on the ocean floor such as earthquakes, erupting volcanoes, landslides (tsunamis).

Through this article, we will take a deeper look at how waves are formed, what causes them to break, and which ones you should be surfing.

  • Save
How Are Waves Formed? (& Best Type of Wave for Surfing)

What Are the Different Types of Waves?

As mentioned above, there are three main types of ocean waves: Wind, Tidal, and Groundswell.

Surface Swell

It was created by blowing winds on the surface of the ocean. 

When the wind makes contact with the water, some of the wind energy is transferred to the sea, which makes ripples in the water.

In stronger winds, such as hurricanes or large storms, these waves become much larger and more powerful, thus resulting in larger waves reaching the coastline.

This swell tends to form long rolling waves that build power as they make their way to shore before crashing.

Tidal Waves

Tidal waves are caused by the gravitational pull on the ocean from the moon, sun, and the earth.

These waves are small and non-surfable. However, the changing tides do play a large role in the surf conditions of many locations.

The term “tidal wave” is often incorrectly used to describe large destructive waves such as tsunamis. However, these are not the same.

READ ALSO  Why Do Surfers Wear Uggs? (The Real Truth)


When there is a disturbance on the ocean floor, large amounts of water are displaced, which forms a huge rolling swell that makes its way towards the coastlines.

Groundswell is formed by underwater earthquakes, landslides, oceanic volcanoes, and at times, falling ice shelves.

Waves formed in this manner do not crash onto the coast but instead, thanks to the raised waver level, roll onto the shore, causing massive damage and reaching far distances inland.

Constructive vs Destructive Waves

Constructive waves have a lower frequency, are less steep, and reach the shore in a rolling manner, while destructive waves are steeper, have a higher frequency, break with a high peak and break onto the shore with crushing power.

Constructive Waves

Constructive waves have a low frequency and can roll in as little as once every 8 – 10 minutes.

Thanks to the low frequency, constructive waves have a gentle slope and roll onto the shore, making them perfect for longboarding.

Constructive waves are responsible for building up sand on coastlines.

Destructive Waves

Destructive waves form when large amounts of water are added to the ocean through high wind and storms.

These waves tend to travel large distances with high frequency and power.

These waves have large backwash, which causes them to roll and break with high peaks as they crash onto the shore.

These waves tend to be smaller than constructive waves but break more frequently with greater power.

Destructive waves are responsible for breaking down coastlines.

Factors That Cause a Wave to Break

As deepwater ocean swell makes its way to the shore, the ocean bed becomes shallower, which causes friction at the underside of the wave.

This friction slows down the bottom of the wave, which causes a rolling motion, as well as increases the vertical height of the wave.

Depending on the ocean bed near the shore, the wave will perform differently.

For example, a gently sloping sandy-bottomed beach will form slowly crumbling waves, while a sharp change in water depth, such as a reef, will cause a wave to peak up and break in a crushing and often hollow fashion.

READ ALSO  How Much Does Surfing Cost? (Explained for Beginners)

Ocean floor beds that change the way a wave breaks include but are not limited to:

  • Coral, rock, and kelp reefs.
  • Sandbanks.
  • Points, or landmasses.

Other factors that are involved in breaking waves:

  • The slope of the shoreline.
  • Material of the ocean bed.
  • The speed of the wave.
  • Swell size.
  • Whether the wave is constructive or destructive.
  • Wind speed and direction.

What Determines the Size of a Wave?

A wave’s height is determined by the wind speed and the fetch (the distance across the ocean that the wind blows in a single direction).

The longer the fetch and faster the wind speed, the greater the wave size will be.

Large waves only form when a combination of fast wind speed, the correct wind direction, and a long enough fetch.

Apart from these three factors, the size of the wave will be limited by obstetrics in its paths such as icebergs, islands, and other large obstructions.

Bays, points, harbors, piers, the angle of the ocean bed, and the consistency of the coastline will all further change the size of the wave.

If a bay is open to the ocean and the swell rolls in straight to the coast, you can expect larger breaking waves.

If swell needs to travel around a harbor wall or turn to enter a bay, the waves will lose some power, and therefore result in smaller waves when they reach the beach.

Do Surf Spots Always Have the Same Type of Wave?

The wave type, consistency, size, power, angle, and period are never consistent at a single break.

Wind direction and speed on the shore and the out at sea weather conditions will determine how the swell enters a coastline.

Furthermore, changes in the ocean floor, such as moving sand backs or a change in the angle of the ocean bed will change how waves break and form on the beach.

What Is the Best Type of Wave for Surfing?

The best type of wave for surfing is always up to an individual, what they are comfortable with, their surf style, their skill, as well as what surfboard they use and their body shape.

READ ALSO  Can Surfboards Be Used As Paddle Boards? ( 5 reasons why it's not a good idea )

That being said, some key factors make a good wave:

  • Wave period: The greater the wave period, the fewer waves will roll in, but they will be larger and more powerful.
  • How clean the wave breaks: The cleaner the face of the wave, the easier it is to surf.

When a wave has a clean face, you will be able to ride it further.

Waves that break in all directions create short messy rides. This usually occurs in onshore winds.

  • Size of the wave: The size of the wave is important as waves that are too small will not have enough power to propel you forward.

Waves that are too large for a location will not behave as more suited swell does and often don’t break over the reefs or break too close to shore.

  • The angle of the wave: Depending on your skill level and the type of surfboard you enjoy surfing, wave angle plays a big part in what you may consider to be a perfect wave.

Steep waves are great for surfers who prefer fast, performance-like surfing on a shortboard, while slow rolling waves with smaller gradients are ideal for those who enjoy cruising on a longboard.

If you are looking for clean breaking, rolling waves perfect for longboarding, then constructive waves formed from strong winds out at sea will be perfect.

If you are looking for something a little more intense, then seeking out destructive waves breaking over a shallow beach could be exactly what you are seeking.


The best waves for surfing are formed from changing pressure systems out at sea. This change in pressure causes winds that build up the swell.

If the distance between land and the storm is long enough and the direction of the wind stays constant, a huge swell will arrive at the coastline.

With the combination of the ocean bed (which slows the lower side of the wave down), this swell causes the wave to peak up and break, thus creating a wave perfect for us surfers.

  • Save
Scroll to Top
Copy link