Waves, tides and rip currents: understanding the ocean and its dangers
Waves, tides and rip currents shape beaches and influence swimming and surfing conditions. In Lacanau, these phenomena constantly change under the influence of swell, wind and sandbanks. Understanding how they work helps you read the ocean better, choose the right conditions for surfing and avoid certain dangers.
Key takeaways
- Waves are mainly generated by wind. Their shape also depends on water depth and the seabed.
- Tides, caused by the gravitational pull of the Moon and the Sun, change sea levels and surfing conditions.
- Rip currents can form in sandy depressions where powerful currents flow out to sea.
- Safety relies on observing conditions, respecting supervised swimming areas and knowing the right safety procedures.
How do ocean waves form?
Waves form when wind transfers its energy to the surface of the water. The stronger the wind blows, the longer it lasts and the greater the distance it travels over the water, the bigger the waves can become.
Offshore, these undulations travel as swell. As they approach the coast, waves encounter shallower water: they slow down, become steeper and eventually break.
Their size and shape mainly depend on swell strength, local wind and underwater topography. This is why conditions can vary significantly from one beach to another.
To learn more, discover the 10 things to know before your first surf lesson in Lacanau, including how to observe ocean conditions.
What are the different types of waves?
There are several types of breaking waves, depending on the slope of the seabed and the characteristics of the swell.
| Wave type | Characteristics |
|---|---|
| Spilling wave | Breaks gradually, producing whitewater, often suitable for learning in small surf conditions. |
| Plunging wave | Its lip curls forward and can form a barrel sought after by experienced surfers. |
| Surging wave | Collapses suddenly onto itself, producing a powerful breaking wave. |
The seabed also plays an important role. Beachbreaks, such as those in Lacanau, produce waves over shifting sandbanks. Reefbreaks form over reefs, while pointbreaks break along a headland or cape.
Be careful of shorebreak, a wave that breaks directly near the shoreline and can cause violent falls in shallow water.
How do tides work and how do they affect waves?
Tides are periodic changes in ocean levels, mainly caused by the gravitational attraction of the Moon and the Sun.
On the beaches of Lacanau, they change the water depth above sandbanks and therefore influence how waves break.
- At high tide, some sandbanks are more deeply submerged and waves may break closer to shore.
- At low tide, sandbanks are covered by less water and some waves become hollower.
The tidal coefficient, ranging from 20 to 120 in France, indicates the extent of the tidal range, meaning the difference in water level between high and low tide.
However, there is no single ideal tide for surfing in Lacanau: it all depends on the swell, wind, sandbanks and the surfer’s level. Beginners should avoid high tide.
During surf lessons for teenagers and adults in Lacanau, lesson times are adapted to the tides and participants’ abilities to select the most suitable conditions.
How can you identify a rip current and why is it dangerous?
A baïne is a depression carved into the sand by water movement. When water accumulated near the shore flows back out to sea, it can create a rip current capable of quickly carrying a swimmer away from the beach.
A rip current can sometimes be identified by several signs:
- An area where fewer waves break compared with the surrounding water.
- A channel of darker water between two sandbanks.
- Sea foam that appears to move offshore.
These signs are not always visible. An apparently calm area can therefore be dangerous, even for a strong swimmer.
Contrary to popular belief, rip currents are not dangerous only during a rising tide. Their strength depends in particular on the swell, the tide and the configuration of the sandbanks.
What should you do if you get caught in a rip current?
The first thing to remember is not to fight the current by trying to swim directly back to the beach. Doing so can quickly lead to exhaustion.
Here are the steps to follow:
- Stay calm and control your breathing.
- Do not swim against the current.
- Raise one arm and call for help.
- If possible, swim parallel to the beach to escape the current.
- Gradually make your way back to shore once the current weakens.
If you become tired, it is better to float to conserve your energy and wait for help. To prevent these situations, always choose supervised swimming areas and follow lifeguards’ instructions.
Learning safety rules begins with the very first lesson. Discover what happens during a surf lesson in Lacanau, from the beach briefing to entering the water.
Learn to read the ocean to surf safely
Understanding waves, tides and rip currents helps you better anticipate ocean conditions. At Ocean Ride, discovering how the ocean works is part of learning to surf.
Discover our surf lessons in Lacanau to learn how to recognize waves, improve your skills and enjoy the ocean with the guidance of qualified instructors.
FAQ: your questions about waves, tides and rip currents
A baïne is not necessarily safe at low tide. Currents can develop depending on the swell, water depth and configuration of the sandbanks. It is best to swim in a supervised area.
Swell refers to waves that travel away from the area where the wind generated them. The term “waves” is more general and describes undulations on the surface of the water, particularly as they approach the coast and break.
There is no universal answer. Conditions suitable for beginners depend on the swell, wind and sandbanks. An instructor chooses the right time and the most suitable area for the participants’ abilities.
