How Are Waves Formed?
The last thought going through your mind when a wave is bearing down on you is “Where did this lump of oceanic energy originate from?”.
Most likely, you’ll be more focused on positioning, popping up and riding it to shore.
However, understanding how waves are formed can deepen your appreciation for this powerful force of nature.
Not only that, but it’s actually a very interesting topic!
We’re not scientists at Rise Up, but we do love learning about Mother Nature. This article is our attempt to explain the basics of wave formation in a fun and easy-to-understand way.
With any luck, the next time you’re out surfing, you’ll have a better understanding of what’s going on around you.
What are waves?
Waves, or more specifically ocean waves, are simply a visible manifestation of energy that’s moving across the surface of the ocean.
This energy can come from various sources (wind, tides, earthquakes or seismic events in the form of tidal waves or tsunamis). It’s defined as a series of rising and falling swells on the ocean’s surface.
The energy of a wave moves in a circular motion, with the water particles moving up and down as the wave passes through. A wave crest rises above the water level, while a wave trough dips below it.
As you might know from experience at our surf retreats, waves come in all shapes and sizes.
There are big waves, small waves, powerful waves and weak waves. There are also gentle waves and potentially hazardous waves – all of which are created and shaped in different ways by different forces.
Key takeaway: Energy passing through the water is what creates waves. Surfable waves are created by wind energy while most long waves (called tsunamis) are created by seismic energy.
How are they formed?
Not all waves are created equal, and in our article about how to read a surf forecast, we say as much. Waves, no matter their size, all get their start in the same place – the open ocean.
At this point we could launch into an overly technical explanation of how the wind’s energy is transferred to the water and forms waves, but we’ll save you the headache.
All you need to know is that wind-driven waves, otherwise known as surface waves, are formed by the friction between wind and water over an extended distance. It’s the same effect as when you blow over the surface of a drink.
The air (or wind) from your breath creates ripples. Ocean waves are subject to the same phenomenon, but on a much larger scale.
Surface waves occur constantly all over the world’s oceans, but only become surfable when they encounter shallow water.
Key takeaway: The more the wind blows, the higher the wind speed and the further out to sea the waves originate, the larger and more powerful the resulting beach, reef or point break waves will be.
When do “oceanic” waves become “surfable” waves?
Oceanic or surface water waves become “surfable” waves when they reach shallow enough water that the bottom of the ocean starts affecting their movement.
Picture a reef, beach or point break that’s much shallower than the deeper water further out to sea. When the waves reach these shallower areas, the bottom of the ocean starts to have an impact on them.
In layman’s terms, the shallower bottom essentially “trips” the waves, causing them to stand up and fall over (otherwise known as “breaking” to surfers).
It’s said that for a wave to break, the ocean floor needs to be at least 1.3 times the wave’s height, but this can vary depending on the shape and slope of the ocean floor.
Key takeaway: Wave energy is most commonly transformed into surfable waves when the ocean floor is a certain depth compared to the wave’s size. Crazy how this movement of energy can actually be ridden and even rewire our brains, right?
What role do the sun and moon play in wave formation?
Understanding ocean waves means also understanding the role that the sun and moon play in their creation. Or more specifically, how tides play a role in wave formation.
Tides are caused by the gravitational pull of the moon and sun on the Earth’s oceans. As the moon orbits around Earth, it creates bulges in the ocean’s surface that result in high and low tides.
In addition to swell size and direction, tides are an important factor to consider when planning a surf session, as they can greatly affect the quality and shape of waves.
An incoming tide generally brings bigger surf, especially when the forecast predicts that the swell is increasing. Likewise, a switch in the tide can cause the frequency of waves to slow down and/or become smaller.
This isn’t always the case, but it’s an old rule of thumb for most surfers.
Key takeaway: The sun and moon both play a role in wave formation through their effects on tides, which can greatly impact the shape and quality of waves.
How does severe weather create more potentially hazardous waves?
Severe weather like a storm surge, seismic event, volcanic eruptions, hurricane or severe storm can create much larger, more powerful and potentially hazardous waves.
Tidal waves or tsunamis are an extreme example of this, where seismic energy from an earthquake or underwater volcano creates massive waves that can cause destruction when they reach land.
Likewise, hurricanes can send swell energy in the form of long period waves to distant coastlines.
For example, a hurricane in the Caribbean can create powerful waves in New York or even Europe, even though the storm is hundreds or thousands of miles away.
These waves are generally bigger than wind-generated waves. And on that note, if big waves scare you, just know that our yoga guru Cici has some epic tips on overcoming your fear of bigger waves.
Key takeaway: Waves are simply the outward manifestation of energy in motion. They can come from various sources including severe weather in the form of hurricanes or earthquakes. These waves can be incredibly powerful and potentially hazardous, making it important to always stay aware of weather conditions before heading out for a surf.
Wrapping up
Without waves we’d probably all be snowboarding or wakeboarding. So we have a lot to thank Mother Nature for… even if we sometimes curse her for sending us flat spells or hectic storms.
Knowing how waves are formed and what factors affect them can not only give you a better understanding of the ocean, but also make you more connected to the sport of surfing. And that’s what it’s all about, right?
We love going in-depth about these topics and sharing our knowledge with you. Hopefully, you’ve learned a thing or two as well.
Let us know in the comments below if you have any questions or additional insights about wave formation. We’d love to hear them!
