A guide to understanding how, where and why ocean waves are formed.
Waves are created by localised winds or storms out to sea that break when they reach land. To understand waves, you need to understand how they are created and what factors affect the size, shape and speed. The main factors are the wind, distance travelled, and time. At Newquay Activity Centre, nestled in the heart of Cornwall’s vibrant coastal scene, we’re not just about catching waves; we’re dedicated to equipping all beach goers with the knowledge to enjoy them safely.
We are constantly aware of the changing sea conditions for keeping our customers safe in the water, and finding the best surfing spots. With over two decades of experience we know that knowledge is your best tool to staying safe as a sea user. Understanding how waves are created and what impacts their size and strength will not only keep you safe, but will also help you become a better independent surfer. We’ve curated a comprehensive guide with our combined experience and knowledge dedicated to helping you unravel the mysteries of wave dynamics
What is a wave and how is it formed?
Waves begin to form far out to sea where low pressure weather systems create storms and strong winds. The winds create ripples and other disturbances on the surface of the water which grow larger as more energy moves from the air to the water, evolving into what we call swell. The waves ripple out in all directions across the ocean towards the shore, building momentum and energy as they move towards land. When swell reaches land and begins to break in shallower water, they become sets of waves. A set is a group of waves where each wave shares similar dimensions and speed. If you’re into the science, you can get more in depth with this video on how an ocean wave forms.
The size and strength of breaking waves depends on:
- The distance travelled (the fetch)Â
- The windÂ
- The tideÂ
- The contours of ocean floor
Fetch
Fetch refers to the area or distance across the ocean the wind has travelled to create waves. The further a distance the wind has travelled, the bigger the fetch, and the bigger the wave height. Think of the fetch as the beginning of a waves journey to the beach.
Wind
Duration and speed
The velocity of the wind is the speed the wind is moving in any given direction. The speed alters the time it takes the swell to move across the ocean to the shore. If the wind speed is slow, it will create smaller waves. If the wind speed is faster it will reach the shore quicker, resulting in bigger waves.
Localised wind direction
Localised winds occur on a smaller scale and usually last between a few hours to a day. Localised winds and the direction they come from can determine how waves will break. This is usually broken down into offshore, onshore and cross shore winds.
Offshore winds
Offshore winds are winds moving from land out to sea, they tend to create cleaner, more glassy waves. This is because the wind blowing into the waves holds back some of the energy of the wave, making it break more smoothly. The face of the wave is cleaner for longer, giving surfers more space to play.
Onshore winds
Onshore winds are winds pushing from the sea towards land, which usually mean messier, choppier waves which are harder to surf. The wind is hitting the back of the waves causing them to crumble faster, which makes them harder to catch especially as a beginner surfer.
Cross shore winds
Cross shore winds blow across the beach either to the left or to the right. Cross shore winds can mean the waves break at an angle rather than directly into the land. These winds can make how a wave is going to break difficult to predict
Swell
Swell is the name given to the wind travelling across the ocean after it has been created by storms far out to sea. When the swell reaches the shallower water close to the land it rises up out of the water, forming the waves we see breaking at the beach.
Swell period or wave period will come up a lot when looking at surf forecasting. The swell period is the time between swells. It’s taken as an average time in seconds between the crest (highest point) of each wave. This is a great indicator for the force and power of the waves. A swell period of less than 10 seconds is likely to be less powerful, but can be messier. Longer than 10 seconds will give more powerful, cleaner waves. The longer the swell period, generally the better the waves.
Surf forecasting will tell you the swell height, and the wave height. Swell height is the height of the waves out to sea before they break. The wave height is the height at which the waves are breaking. Check out surflines blog for more detail on the difference between surf and swell.
There’s often confusion between swell and surf but to keep it as simple as possible, remember that swell travels across the ocean, and when it comes into shore it breaks creating surf.
Tides
Tides are the movements of the ocean in response to the forces of the sun and the moon. They are a massive factor in finding a good location for surfing. There are two high tides and two low tides every day caused by the gravitational pull of the moon and the sun.
There are two kinds of tide, spring and neap. Both tides occur twice every lunar month. On a spring tide, high tides will be higher and low tides will be lower. On a neap tide, the high tides will be lower and the low tides will be higher, or put much more simply:
Spring Tides – high highs and low lows
Neap Tides – high lows and low highs
Always check the tide before you go surfing. There’s nothing worse than rocking up at the beach only to find the waves breaking right on shore, at high tide with no surf. Some spots are only surfable on certain tides, or are only safe on certain tides. Always check ahead and if you’re unsure ask a local.
Ocean Floor
The contours and shape of the ocean floor impacts how swell behaves as it approaches the coastline, shaping the way the waves break.
Refraction
One of the ways this happens is through a phenomenon called refraction. Refraction occurs when a wave encounters a change in the depth of the ocean floor as it moves into shallower water. The transition to shallow water slows down and changes the shape of the breaking wave, resulting in changes to its direction and height. When watching the waves from the shore, you can see how waves sometimes move in various directions, occasionally intersecting or crossing paths with each other. This is a result of the contours of the ocean floor, impacting the waves above. Wedges are another result of refraction. Wedge waves are the aftermath of refraction causing a wave to collide with a second incoming wave, creating a wedge wave, bigger than the previous two waves.
Reef breaks
Reef breaks are famous for creating waves of perfect speed and shape for catching barrels. A reef is a collection of rocks or corals along the ocean floor. These are often but not always further out to sea. Reef breaks create waves when the swell hits the reef and the wave breaks over the top of it. They’re popular with surfers because when the swell comes from deeper water and suddenly hits the rocks or corals of the reef, it breaks quickly creating steep, powerful and long waves.
Sandbars
Sandbars are common in the areas around Newquay due to the long sandy beaches. As the name suggests a sandbar is a long ridge, built up of sand or sediments under the water. The sandbars are formed by tides or currents pushing sand into lines, sometimes they become so big they are exposed above the waterline. Sandbars can shift around and move in relation to the tides and storms, so they aren’t always in the same place. As the sandbar makes the ground higher, the incoming waves will break over the top once they hit the shallower water.
Why Do Waves Break?
Waves break because the energy of the swell is interrupted as it moves into shore. This can be a mixture of the oceans topography, energy and gravity. As swell approaches shallower waters, it encounters the sea bed which initiates the process that makes waves break. While the wave maintains its velocity, (its speed and direction) the energy that was within the wave starts to drop, in particular in the lower part of the wave that is hitting the seafloor.
The wave’s forward motion is constant, however the energy is reduced. This motion forces the water to be pushed upwards making a wave that we would recognise from the beach. The energy pushing the water up results in the wave getting higher. The water begins to move faster on top of the wave than at the bottom of the wave. This combined with gravity’s pull causes the crest of the wave to topple over, collapsing on itself culminating in a breaking wave. There’s plenty more scientific discussion over how and why this happens, to delve deeper check out this  video on the formation of waves.
Wave Types
There are so many different types of waves, all with multiple names, each characterised by distinct behaviours and features. The three primary types of waves, especially found in Cornwall are spilling, dumping and surging waves. This quick guide will help you to recognise and understand how each type is formed, for a more exhaustive list of wave types, check out the surfer slang glossary at the bottom of this blog.
Spilling waves
A spilling wave is a gentle, consistent wave that will break softly as it reaches the shoreline. Usually found on beaches where the ocean floor rises gradually. These waves are best for surfers who are just starting progress to surfing in deeper water and catching unbroken waves.
Surging waves
Surging waves are waves which break very little or not at all. A wave loses power and momentum when it breaks, so surging waves can be very dangerous as they can be very powerful. They often take people by surprise on steep or rocky shores, knocking them off their feet and pulling them into deeper water.
Dumping waves
Dumping waves are powerful waves that often break late in shallow water. They are likely to rear up suddenly and break downwards with extreme force. When dumping waves break close to the shore, they often get called a shorebreak. Shorebreaks or dumping waves are dangerous for beginners or swimmers as they break hard and fast in shallow water and can cause spinal injuries. Dumping waves are caused when the wave travels quickly from deep to shallow water which results in the wave rapidly slowing down and closing out.
Wave Height
Wave height is the measurement of the breaking wave. It’s measured in feet as the distance between the crest/peak, (highest point of the wave) and the trough, (the lowest point of the wave). Wave measurements aren’t an exact science, it varies across the world and is usually taken with a pinch of salt. Surfers often refer to wave heights as head-high, waist-high, or ankle-high. These less defined measurements are taken as if you are surfing the wave. For example, if a surfer was on a wave and it came up to their waist, it would be considered a waist high wave, this is called the surfable wave face method.
Wave Height
With all this information it’s easy to feel intimidated by sea conditions. However, there are plenty of tools to help you out. Surf forecasting is made easier with the assistance of the surf forecasting apps. There are a number of different apps to help you assess the sea conditions, the main ones being Surfline, Windy and Wind Guru. Of the three, Surfline is the easiest to use to get the information you need. Understanding the surf forecasting apps can seem like a science in itself, but there’s plenty of videos and articles available on how to read them. We recommend these videos by our very own Rob Barber, European bodyboard champion, on and tips for wave selection. As well as this Women + Waves video on how to read a surf forecast. Â
Surfer Slang Glossary
Surfing has its own language, and that doesn’t stop when it comes to waves. This handy glossary covers the most common surf slang you’ll come across when talking about waves and the wave conditions.
A-Frame – A-frame describes a wave with a perfect A frame peak breaking left and right.
Barrel – The ultimate goal of any surfer – a barrel or tube is a wave that forms a hollowed-out centre like a tunnel which surfers can ride through.
Choppy – When surfers say the waves are choppy, it means that the waves are bumpy, shorter and messy. Generally more difficult to surf in, and often caused by onshore winds.
Clean – A clean or glassy wave is a wave that has a smooth surface that has not been disturbed by winds. Often a result of offshore winds.
Clean Up Set – A clean up set is the term given to a wave or set of waves considerably larger than the norm, that break further out to sea. These can catch the surfers in the line-up out and ‘cleans’ (Wipes out) those caught inside from the line-up.
Closeouts – A close out is when a wave breaks at the same time across the whole wave, rather than peeling left or right.
Green Room – Being ‘in the green room’ describes the moment a surfer is inside the hollow of a barrel.
Lefts – Lefts are the term used for waves that break to the left, from the surfers perspective.
Messy – Messy waves are waves that have been disturbed by the wind and break roughly, often with a lot of spray caused most frequently by onshore winds.
Peaks – A waves peak is its highest point, where it breaks first.
Peelers – Peelers are waves that form cleanly, and gradually break peeling either left or right.
Pit – The pit is another term for a barrel or tube, if a surfer was ‘in the pit’ or ‘got pitted’ they were in the hollow of the barrel.
Rights – Rights are the term used for waves that break to the right, from the surfers perspective.
Shoredump – A shoredump or shorebreak is a term for a wave that breaks quickly and steeply high on the beach in shallow water. Usually caused by a beach that slopes steeply up.
Widow Maker! – The nickname given to the highly dangerous, big wave spot also known as The Cribbar. Formed by a reef just north of Fistral Beach in Newquay, this spot produces Britain’s biggest waves which can be found here just a few times a year.
Staying Safe on the Beach
Getting in the know is the best way to stay safe on the beach, there’s plenty of dangers in the waves, and knowing what they are is the first step to avoiding them. Newquay Activity Centre prides itself on being the best in the business, and that means arming you with the tools to keep you safe, not just with our guide to understanding waves, but also our guide to staying safe on the beach.
The ocean can be a marvel and a mystery, but with this guide we hope to unravel the whys and hows of understanding waves in a way that benefits every ocean goer. Curiosity and adventure go hand in hand here at The Newquay Activity Centre, whether you’re taking your family bodyboarding, are learning to surf or are embarking on outdoor instructor training.
Freddie Allan-Gething, Centre Manager and Beach Lifeguard Trainer Assesor says:
‘Water is an unpredictable and dangerous environment. Rip currents can be difficult to spot but are sometimes identified by a channel of churning, choppy water on the sea’s surface. Please use one of the lifeguarded beaches across Newquay, swim between the red and yellow flags and feel free to speak to any of our lifeguards for safety advice. No matter how experienced you are, anyone can be caught out by a rip current as the strong currents can quickly sweep people out of their depth in a matter of seconds.’
‘Also, stand up paddleboarding(SUP) and kayaking are activities that are becoming increasingly more popular however, now it is more important than ever that the public are aware of the potential risks involved with the likes of SUP and kayaking. These are wonderful activities; however, it is vital that individuals are well prepared and informed before getting in the sea. Conditions change daily, and even hourly so before entering the water, let your friends or family know where you are going and familiarise yourself with local hazards. Furthermore, we advise wearing a buoyancy aid and taking a means of communicating with someone in case you do get into difficulty.‘
Getting in the know is the best way to stay safe on the beach, there’s plenty of dangers in the waves, and knowing what they are is the first step to avoiding them. Newquay Activity Centre prides itself on being the best in the business, and that means arming you with the tools to keep you safe, not just with our guide to understanding waves, but also our guides to staying safe on the beach and recommending all beach goers read the RNLI guide to beach safety.Â
The ocean can be a marvel and a mystery, but with this guide we hope to unravel the whys and hows of understanding waves in a way that benefits every ocean goer. Curiosity and adventure go hand in hand here at The Newquay Activity Centre, whether you’re taking your family bodyboarding, are learning to surf or are embarking on outdoor instructor training.Â
