Why Madeira's peak ridges are so sharp, and why they keep crumbling

If you've walked from Pico do Areeiro towards Pico Ruivo, you know the feeling. The path squeezes along a crest of rock, the clouds sit below you, and on both sides the ground just falls away into green. Visitors often ask us whether they're walking around the rim of an old crater. It's a good question, and the real answer is better than "yes". It also explains why the high trails close so often after bad weather.

Key facts

• Madeira's highest peaks are Pico Ruivo (1,862 m) and Pico do Areeiro (1,818 m) (IFCN management plan for the Central Mountain Massif, 2009).
• Their sharp crests are hard volcanic dykes left standing by erosion (same plan).
• Madeira first rose above the sea about 7.0 to 5.6 million years ago (Ramalho et al., 2015, peer-reviewed).
• The Areeiro weather station recorded an average of 2,939 mm of rain a year, and the area averages 241 days of fog a year (IFCN plan, 2009, long-term averages).
• PR 1 is open in both directions between Pico do Areeiro and Miradouro da Pedra Rija; the eastern branch via Pico das Torres is closed (IFCN trails list, updated 2 October 2026).

What the sources say

It isn't a crater. Madeira's peaks are what's left of old volcanic rock after millions of years of erosion. IFCN, Madeira's regional forest and nature agency, says in its management plan that the island's present relief was shaped by erosion acting on rocks of different strength. When you stand at Pico do Areeiro and look down towards Curral das Freiras (literally "the nuns' corral", the deep valley village to the west), a geology explainer in Times of Madeira (19 October 2026) describes it as a valley cut by water, not a collapsed crater.

The island is older than it looks. A 2015 study in the journal Geochemistry, Geophysics, Geosystems (Ramalho and colleagues) dated Madeira's first emergence above the sea to about 7.0 to 5.6 million years ago. Interestingly, it rose mainly through uplift, before the later eruptions built most of the island we walk on today.

The mountains are mostly soft, held together by hard "walls". IFCN's plan for the Maciço Montanhoso Central (the Central Mountain Massif, the protected high ground around the peaks) describes the bulk of the massif as pyroclastic material, meaning ash, cinders and volcanic blocks thrown out by old eruptions, with a few basalt lava flows in between, much of it heavily weathered. Running through all of it is a dense network of dykes: sheets of magma that once forced their way up through cracks and cooled into hard rock. They run in every direction and tend to converge around Pico Ruivo.

Rain did the sculpting. Soft ash wears away faster than hard dyke rock, which geologists call differential erosion. According to the IFCN plan, Pico Ruivo and Pico do Areeiro owe their sharp relief to large dykes that resisted erosion while the material around them washed away. The plan calls these exposed dykes "muralhas" (walls) and says they form long, abrupt crests and sometimes needle-like peaks. Some of the rocks in this area are trachyte, a paler volcanic rock, and the plan notes that rocks here are strongly leached and turn whitish.

And the rain hasn't stopped. The plan gives an average of 2,939 mm of rain a year at the Areeiro weather station, with a maximum of 522 mm in a single day, plus about 241 days of fog a year and winds mostly from the north and north-east. These are long-term figures from a 2009 planning document, not this year's weather. The plan is blunt about the result: water cuts deep gullies in the loose pyroclastic rock and leaves sheer walls that often collapse under gravity.

What we see up there

This is where the geology stops being abstract. The process that made those ridges so beautiful is still at work, every winter, right next to the path. Most of us who grew up hiking here have learned to read the mountain a little. After a wet week there's fresh grit and small stones on the steps that weren't there before, and every year some stretch of railing or path is being repaired somewhere. On the Areeiro–Ruivo route, the tunnels and long stairways show how little room the ridge leaves for a path at all.

So when a high trail closes for repairs, or only part of it is open, it isn't red tape. It's the island doing what it has always done, and the trail teams catching up. The way you can walk PR 1 (Vereda do Areeiro) has changed more than once this year, so the official list is the only place to trust on the day.

How to walk the ridges well

• Check the official status the same morning. Use IFCN's classified-trails list, not an old blog post or a tour leaflet. Pay the trail fee and book on SIMplifica where it's required.
• Give the mountain a day after heavy rain. If it has poured overnight, a lower forest walk or a levada (one of Madeira's irrigation channels with a footpath alongside) is often the kinder choice, as long as it's open too.
• Stay on the built path and behind the railings. Those dykes and crumbly ash slopes are exactly what's falling apart. A shortcut or a photo off the edge can loosen material onto someone below.
• Leave the rocks where they are. Don't take stones home or stack them on slopes this loose.
• Expect fog, and plan for it. Start early, carry a warm layer and a headtorch, and turn back if the cloud closes in and you can't see the edge.
• Report damage. IFCN asks walkers to report rockfalls, fallen trees or anything blocking a classified trail.

Quick answers

Is Pico do Areeiro a volcanic crater? No. The peaks and ridges are hard dykes left standing by erosion, according to IFCN's management plan.

How old is Madeira? The island first rose above the sea about 7.0 to 5.6 million years ago, according to a 2015 peer-reviewed study.

Is PR 1 open? On 2 October 2026 IFCN listed it as open in both directions between Pico do Areeiro and Miradouro da Pedra Rija, with the Pico das Torres branch closed. Check the IFCN list on the day.

Why it's worth knowing

Once you know you're walking on an old volcano's skeleton, the Areeiro–Ruivo ridge looks different. Those pale fins of rock are the parts tough enough to survive, and the valleys are millions of years of rain at work. Walk it slowly, give it a day after storms, and leave it as you found it. That's how we keep it walkable a little longer.