In the Canaries the islands get younger towards the west
Between Fuerteventura and El Hierro there are some twenty million years of difference. From that come Lanzarote's 670 metres and Teide's 3,715, and from height comes everything else: the rain, the forest and the shape of each island.
The question almost everyone planning a trip to the Canaries asks is which island to choose, and the usual answer is a list of clichés: Lanzarote is lunar, Tenerife has Teide, La Palma is green, Fuerteventura has beaches.
All of it is true, and all of it has a single cause. The islands were not made at the same time, and the age difference between the oldest and the youngest is about twenty million years.
01 A thousand-kilometre ribbon of islands
The archipelago lines up east to west off the African coast, and that alignment is no accident. The classic explanation is a hotspot: a more or less fixed source of magma in the mantle, over which the African plate has been drifting.
If the plate moves and the source does not, each stretch of crust passes over it, is punctured, builds an island and carries on. The result is a row of islands whose age increases in the direction of movement. Here, eastwards.
The figures fit the model. Lanzarote and Fuerteventura, the two eastern islands, emerged between 16 and 22 million years ago. Gran Canaria, Tenerife and La Gomera, in the middle, are between 8.5 and 14.5 million. La Palma is around 2 million and El Hierro, the westernmost, 1.1.
Put another way: between Fuerteventura and El Hierro there are some 400 kilometres of sea and some twenty million years of difference. Travelling from one to the other is going through the biography of an island from the end back to the beginning.
02 Age is measured in metres
The quickest way to check the series is to look at each island's highest point. A volcanic island does not stop growing while the source feeds it, and starts coming down as soon as it stops: erosion and the subsidence of the edifice itself wear it away.
Lanzarote reaches 670 metres at Peñas del Chache and Fuerteventura 807 at Pico de la Zarza. They are the two oldest islands and the two lowest. At the other end, La Palma reaches 2,426 metres at Roque de los Muchachos and Tenerife 3,715 at Teide.
The cleanest contrast is between the extremes: Fuerteventura is twenty times the age of La Palma and a third of its height. And in between sit Gran Canaria, with 1,949 metres at Pico de las Nieves, La Gomera with 1,487 and El Hierro with 1,501.
03 And height decides the water
This is where geology turns into landscape. The trade wind blows over the Atlantic at this latitude, a north-easterly loaded with moisture, and that moisture only condenses if something forces it to rise.
An island of 670 metres forces nothing: the air passes over it and carries on. An island of 2,400 metres intercepts it, makes it climb the northern flank and unloads it as persistent low cloud, what the islands call the sea of clouds.
The result is in the rain gauges. At Gran Canaria airport 134.1 millimetres fall a year over 42.6 days, semi-desert figures. The western islands, higher and younger, support on their northern flank a laurel forest that needs constant moisture.
That is why the eastern islands have dunes and the western ones have forest. It is not that they get a different climate: it is that they are tall enough to manufacture their own.
04 The exceptions, which matter
The series is a tendency, not a law, and it is worth saying because on the ground you see it at once. Lanzarote is one of the oldest islands and has the most recent-looking lava fields of any of them.
The reason is that volcanism does not switch off at once. The Timanfaya eruptions, between 1730 and 1736, buried a considerable part of the island under flows that remain bare today. An old island can have very young rock on top.
And conversely, the young islands are still under construction. La Palma had an eruption in 2021, and El Hierro, the youngest of them all, is also the one with the most recent cones. The ribbon is finished at neither end.
05 Ravines, calderas and cliffs
Age is also legible in the shape of the relief, and there the sequence is just as clear. A young island has whole cones, recognisable flows and straight slopes. In time, water opens radial ravines that cut the edifice from top to bottom.
La Gomera is the textbook example of that intermediate phase: no recent volcanism, the central edifice eroded, and a network of deep ravines running from the centre to the sea like the spokes of a wheel.
Calderas are the other marker. Taburiente on La Palma and Las Cañadas on Tenerife are enormous depressions produced by collapses and landslides of the volcanic edifice itself. An island that grows too fast ends up giving way under its own weight.
The great cliffs come from the same process. Those of Los Gigantes, in western Tenerife, drop into the sea from several hundred metres and are the edge of one of those old massifs cut by the sea.
06 How to travel it
The first practical consequence is that the right question is not which island, but which phase. If you want beach and open horizon, go east; if you want forest, ravine and gradient, go west. They are products of the same process at different moments.
The second is that combining two islands far apart in the series pays far better than combining two neighbours. Lanzarote with La Palma shows both extremes; Tenerife with Gran Canaria largely repeats the same thing.
And the third reorders what you look at. If on each island you ask how much cone is left and how much ravine, you stop seeing eight separate destinations and start seeing a single island photographed at eight moments of its life.
