Coastal warnings in the Canary Islands: what they mean and what to do
San Marcos, Icod de los Vinos (Tenerife). A blue day and an apparent calm, and the wave still breaking hard over the rock. Own photograph.
Every so often the Canary Islands government issues a coastal warning, a prealerta por fenómenos costeros. It goes out when the sea is expected to turn dangerous, usually alongside strong winds and heavy swell. It is not a reason to stay indoors, but it is a very good reason to change your plans if you were heading for the beach or a walk along the rocky coast.
There is one figure that puts it in perspective: in the Canaries, drowning is the leading cause of accidental death, ahead of road accidents. That comes from the reports of the Canarias, 1500 km de costa platform, compiled from data supplied by the emergency services, the coastguard and the Guardia Civil.
Three metres of wave is not three metres of water
A three-metre wave is hard to picture. Here is the useful comparison: three metres is about the height of one storey of a building. And that figure is the significant wave height, the average of the larger waves; isolated waves of twice that can and do appear.
That much water does not arrive gently. It arrives with enormous force, out at sea and on the shoreline alike.
No swimming, even where the water barely covers your feet
A red flag means swimming is prohibited, and this is where the most common mistake happens: assuming that ankle-deep water is harmless.
It is not. Water that runs up the sand has to get back to the sea, and that backwash drags outwards with a force that catches out even strong swimmers. One moment of lost balance is enough to end up beyond your depth.
Shorebreak: the wave that breaks exactly where you are
In these conditions many waves break right at the shoreline, in shallow water. This is what surfers call shorebreak, and it is treacherous precisely because it looks harmless from the sand.
A wave breaking like that can pick a person up and slam them into the bottom. The outcome is not a fright: spinal injuries, dislocations and fractures. It happens a metre from the shore, in waist-deep water.
Rip currents, more of them and faster
All the water the storm pushes onto the beach has to return to the ocean, and it does so along the path of least resistance. That is why, during a swell episode, rip currents multiply and pick up speed.
How to spot one and how to get out of it is covered step by step in our guide to rip currents in the Canary Islands. If you take away one thing: never swim against the current.
The coast is dangerous too, even if you never get in the water
This is the part people underestimate most. Waves wash straight over jetties, rocks and seafront promenades. You do not have to go swimming to be in danger.
When the sea is rough, groups gather on piers and rocky ground to watch and photograph the big waves. That is exactly the setting in which the worst accidents happen: the sea appears to be breaking in the same place every time, until one wave reaches far beyond the rest.
This is not our wording. The official advisory issued during these episodes puts it plainly: take extreme care on the coast, do not stand at the end of piers or breakwaters, and do not take risks photographing or filming near breaking waves.
Nor is it an abstract warning. Over the weekend of 8 and 9 November 2025, with a coastal alert in force, the sea left three people dead and more than fifteen injured at various points around the islands. In Puerto de la Cruz, a group of visitors had gathered on the pier to watch the storm, having passed the safety barrier put up in the area, when a wave reached them and swept them into the water. A 79-year-old woman went into cardiac arrest and died despite resuscitation attempts; several others were injured.
If you want to see a storm at sea, watch it from a distance, from high and sheltered ground.
The trap of the "sheltered" rock pools
Visitors often assume that natural rock pools such as El Caletón in Garachico or Charco del Viento are safe during a storm because they are ringed by rock. That is a dangerous illusion.
During a swell episode, big waves clear those stone barriers in one go, fill the pool within seconds and create a powerful suction back towards the open ocean through the natural drainage channels. When a coastal warning is in force, rock pools are off the list.
One well-known case makes the point. El Tancón, in Santiago del Teide, circulates on social media as a natural pool, but it is a bufadero: a sea cave where water and air are forced in and out under pressure. It has caused several deaths in a handful of years, swimming there is prohibited and signs say so. Rescue teams have described the inside of it, on a rough day, as a washing machine on spin.
The sea deceives: the waves that reach further
One detail explains why these accidents catch out even careful people. During a storm the swell is not uniform: most waves break along roughly the same line, and every so often one arrives noticeably larger than the rest, reaching ground the water had not touched until then.
That is why the sea can look manageable for twenty minutes and stop being so in a second. And it is why the reasoning "I have been standing here a while and nothing has happened" is worthless: what has not happened yet is not a guarantee.
Why it comes down to you
The Canary Islands have around fifteen hundred kilometres of coastline. Fencing off or patrolling all of it is simply not possible, so on a bad day there will be no physical barrier stopping you from walking up to the water. Where there is tape or a barrier, stepping past it is precisely the gesture that precedes serious accidents.
Which is why red flags and coastal warnings are not administrative box-ticking: in practice, they are the only warning you are going to get. The authorities raise flags, clear beaches, cordon off areas and fine reckless behaviour, but the last line of defence is always the same one: each person's decision to respect the power of the ocean.
What to do when a warning is in force
Respect the red flag: do not go in, not even up to your ankles.
Keep away from the shoreline, from jetties, from exposed promenades and from natural rock pools.
Do not fish from the rocks or take to the water for any sport in the affected areas.
Keep children and older people well back: on this coast, a safe distance is greater than it looks.
Leave the photographs for another day, or take them from a high viewpoint.
Always follow the instructions of lifeguards and local authorities.
Rescues and reckless behaviour
For a sense of scale: a rescue involving the Emergency and Rescue Group helicopter usually falls between 2,500 and 6,000 euros. Beyond the money, what is really at stake is that every avoidable rescue puts the rescue crews themselves at risk.
The detail on the penalties that already apply and on the legal reform currently going through is in our rip currents guide.
Where to check official information
Warnings are issued by the Dirección General de Emergencias of the Canary Islands government, based on AEMET forecasts. Check the status on the day itself, because a warning can be raised or lifted within hours, and it does not always cover every island, or every coast of the same island.
In an emergency, the number is 112.
The Canaries are worth visiting all year round, and the sea is among the best things about them. That is precisely why it pays to know which days call for admiring it from a safe distance.
