All about the ocean: waves, tides, currents and their dangers

The ocean is the source of many natural phenomena, such as waves, tides and currents. But it can
also be a dangerous place. Understanding how it works is essential to enjoying it while remaining
cautious. This article explains waves, tides and currents, and the risks they entail.

1. Wave formation

It all starts offshore, when warm air meets cold air. This creates a depression, where the wind
blows hard. This wind forms small ripples on the surface of the water, which organize themselves
into waves, called swells. The more powerful the wind and the longer it blows, the more massive
the swell, and the bigger the waves that reach the coast. As we approach the shore, the depth of
the water decreases, compressing the water and throwing the waves upwards, giving rise to larger
and larger waves.

2. The different types of waves

There are several types of wave, depending on their shape and the bottom on which they break:

• Slippery breaking: the crest of the wave falls gently, without projecting forward. This
  happens when the bottom gradually rises.
• Plunging breaker: the crest projects forward, forming a tube into which surfers can plunge.
  This type of wave appears when the seabed rises rapidly.
• Swelling break: the wave breaks close to the shore, forming a shorebreak. These waves
  can be particularly dangerous, as they break in very little water, often at high tide when the
  depth near the shore is great, as at Lacanau.

3. The impact of the seabed on waves

The type of seabed has a major influence on waves. Here are a few examples:

• Beachbreak: waves form on a sandy bottom, whose shape changes regularly according to
  storms and the movement of sandbanks.
• Reefbreak: waves break on reefs, creating regular, predictable waves.
• Pointbreak: waves form on rocks, often with long, hollow waves.
  Beachbreaks, like those at Lacanau, are more unpredictable due to shifting sandbanks, while
  reefbreaks and pointbreaks are renowned for their consistent waves.

4. Understanding the tides at Lacanau

Tides are cyclical movements of the ocean, caused by the gravity of the Moon and Sun. When the
sea level is at its highest, it’s called high tide, and when it’s lowest, it’s called low tide. In Lacanau,
at low tide, the water recedes far towards the horizon, while at high tide, the ocean approaches the
shore. It’s essential to understand the tides at Lacanau, as they directly affect the size and
power of the waves. In France, a tidal coefficient is used to measure the amplitude of the tides,
from 20 to 120: the higher the coefficient, the stronger and faster the tides.
The tidal cycle is also influenced by the Moon. When it is full or new, the Sun, Earth and Moon are
aligned, creating higher tides. In Lacanau, understanding these variations is crucial to choosing the
best time to surf, or avoiding a dangerous situation.

5. Baïnes (Holl of water)

Baïnes are holes in the water near the shore, formed by shifting sandbanks. They give the
impression of being calm, because the waves break less, but they hide very powerful currents.
These currents are formed when the water from breaking waves is carried out to sea. The danger
lies in the fact that these currents can sweep bathers away from the shore very quickly, especially
at high tide.
Although often dreaded, baïnes are not to be avoided at all costs. At certain times of the year, they
can be used for surfing lessons, provided you are supervised by a qualified instructor who knows
how to assess their danger. So it’s important to understand the tides at Lacanau to know when
the baïnes become more risky.

6. Dangers and precautions

Powerful waves, changing tides and the currents of the baïnes make some beaches, like those at
Lacanau, particularly dangerous for unwary bathers. So it’s crucial to understand the tides at
Lacanau and learn to identify the areas where the baïnes are present. Observing the warning
flags, listening to the lifeguards’ instructions and avoiding swimming alone are essential
precautions for enjoying the ocean in complete safety.
The ocean offers some incredible moments, but it’s essential to understand the tides at Lacanau,
as well as other phenomena such as waves and baïnes, to enjoy them in complete safety. Whether
you’re a surfer or just a swimmer, knowing how these elements work will help you make the most
of the ocean while remaining vigilant to its dangers. As part of our surfing courses, Ocean Ride
offers you the opportunity to learn the basics of understanding the sea with our instructors.