Trou de Fer

Interesting facts

The gorge is also known as Trou d'Enfer, or 'Hell's Hole'.

Its main stream, the Bras de Caverne, a tributary of the Rivière du Mât, enters the crater over a 200-metre drop that is often almost dry.

One neighbouring fall leaps from a lip so deeply undercut that more than 200 metres of open air separate it from the canyon floor.

Water leaves the crater through a fall nicknamed the Washing Machine, which turns sharply into the slot canyon and drenches anyone nearby.

The slot canyon below, known as the Corridor, runs for about 3 kilometres, and debris jams sometimes dam it into pools such as the 'Lake of the Eel'.

Springs seeping through the porous volcanic walls of the Corridor feed countless small waterfalls along its length.

Taken together, the cascades into the chasm fall about 725 metres, which French sources cite as the highest waterfall on French territory.

A 1990 expedition filmed for the French TV programme Ushuaïa found a waterproof drum lost by an earlier attempt, with its rolls of film still intact.

That 1990 descent took more than two weeks and needed 15 porters, a doctor and a television cameraman.

The boundary between the communes of Salazie and Bras-Panon runs straight through the chasm.

Why it is worth it

"Iron Hole" is a blunt name for a striking piece of geology: a collapsed volcanic crater on Réunion Island, fed by six separate waterfalls, that empties through a knife-thin slot canyon dropping up to 300 meters over its final undercut cliff — tall enough to rank among the highest waterfalls in France and among the highest anywhere.

Its two halves work differently. The upper section is a wide, amphitheater-like crater catching runoff from several falls at once; from there the water is squeezed into a narrow slot canyon that makes up most of the feature's length before the final plunge. It's a shape better suited to water and rope than to feet.

That's largely why it stayed unmapped for so long. The terrain is steep, unstable, and drenched for much of the year, and it wasn't fully explored until 1989 — not for lack of trying. Earlier climbers who attempted to descend into the gorge are said to have never made it back out. Today the view most visitors get is from a platform at the end of a short, well-maintained trail; actually entering the canyon is still a serious canyoning expedition, not a hike.

Best time to visit

The dry season, roughly May to November, gives the safest and least slippery trail conditions. Cyclone season (December–April) can swell the falls dramatically, but also makes both the trail and any descent into the canyon considerably more dangerous.

Getting there

13 km from Saint-André. Roland Garros Airport (RUN) is about 17 km away.

From the encyclopaedia

The Trou de Fer is a canyon on Reunion Island, off the coast of Madagascar in the Indian Ocean. The primary river flowing through the gorge, which is up to 300 m (1,000 ft) deep, is the Bras de Caverne River, a tributary of the Rivière du Mât. The canyon has two distinct parts: a large crater, which is fed by six prominent waterfalls, and a narrow slot canyon at its outlet, which constitutes most of the canyon's length. The canyon starts at the waterfall of the Bras Mazerine stream and after some 1.4 – 1.8 km from the left side joins the main Bras de Caverne stream. The Bras de Caverne River enters the canyon with a waterfall about 200 m (660 ft) high. This drop is usually dry or has very little water, but between that and the next, 180-metre (590 ft) drop, springs feed the river, which drops over this then drops over a final 300-metre (1,000 ft) undercut cliff into the Trou de Fer in a narrow plume of water.

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