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Grand Raid Réunion – all the dirt(y) you need to know

Photo credit: Grand Raid Réunion

Grand Raid Réunion – all the dirt(y) you need to know


Last updated: 15-Jul-21

by Linda Doke

Are you an ultra-distance junkie who’s seeking ever more monstrous challenges, or maybe a trail runner who’s simply hungry for trail adventures in far flung places where the risk of not finishing the race is real because the challenge is so tough? If you’re not scared, then Grand Raid Réunion is the race you’re hunting for!

Grand Raid as it’s better known – or more affectionately Diagonale des Fous (directly translated madman’s crossing) – is revered in ultra circles as one of, if not THE, world’s most difficult 100 milers.


Réunion is an island in the Indian Ocean about 500 miles east of Madagascar. The island is small, just 970 square miles, roughly the size of Luxembourg, but what it lacks in size it makes up for in heart – dominated by two towering volcanic massifs and beset by massive rock walls and cliff-rimmed cirques, the centre of this circular island, a UNESCO World Heritage site, is riddled with towering mountains, calderas and volcanoes, at least one of which remains active.

The scenery of the Grand Raid course takes in this drama. You’ll traverse from the southwest of the island to its capital in the north, across gnarly rugged terrain, steep escarpments, forested gorges and green alpine meadows in a visually striking landscape that will soak your memory bank for many moons.

The stats

Don’t let anyone tell you otherwise: as 100 milers go, this one is damn tough. Every elite ultra-distance runner who’s anyone has either done, or is planning to do, Grand Raid. Its winners include names like Kilian Jornet, François D’Haene, Benoit Girondel, Julian Chorier, Nathalie Mauclair, Andrea Huser and Nuria Picas.

To put Grand Raid’s degree of difficulty into perspective, in 2011 Kilian Jornet won the Western States 100 in 15h34. The following year he triumphed at Grand Raid, taking a whole 11 hours longer than his WS100 time. Admittedly, that year Grand Raid was almost 4 miles longer than WS100, but it also had more than double the cumulative elevation.

So, here’s the dirt you need to know:

  • race date for 2021:   21-24 October
  • start = Saint-Pierre (10pm), finish = Saint Denis
  • distance: 168km / 104 miles (this varies every year with slight route changes)
  • elevation: 9610m / 31,528 ft with longest ascent 2090m (6857 ft), longest descent 1970m (6463 ft)
  • max altitude: 2204m (7231 ft)
  • average altitude: 1084m (3556 ft)
  • number of entries: 2850
  • cut-off: 67 hours (5pm on 24 Oct)
  • usual percentage of race finishers: 65%


And here’s the dirt no one tells you:


There’s very little flat about the Grand Raid course. The island is volcanic – everything about it is sharp, especially its mountains. Plan your training accordingly – strengthen your legs not only to climb strong, but to handle the relentless hammering of the steep descents.


The mountainous central area of Réunion sees up to 6m (235 inches) of rainfall per year, and the chances of the trails being muddy for the race are high. Thick cloying mud on steep terrain can be… interesting!


The main crop farmed in Réunion is sugarcane, a plant which thrives in hot humid climates. The route passes through several agricultural areas, and the humidity in the sugarcane fields soars.

French speaking

Being a French territory, Réunion’s main language is French. It’s worth knowing in advance that if you’re not bilingual, or at least even slightly conversant in basic French, you will have a very lonely race! (That was me – never before had I run with so many people, yet shared so little conversation.)


Photo credit: Linda Doke

Race start

There is only one major road in Réunion – it’s a ring road highway that goes around the entire perimeter of the island. This means that the only route to get to the start is shared by 2850 runners, and the traffic congestion to get to the race start in the small coastal village of Saint-Pierre is real. Be sure to set off early so that you’re at the start a good couple of hours before the gun goes at 10pm.

No trekking poles allowed

If there’s one race in which you’ll long for the help of poles, it’s this one. But alas, they’re prohibited.

Plan your accommodation wisely

Don’t forget the race is point to point… you don’t want to be THAT poor sod exhausted at the finish line who realises he’s now got to get back to his accommodation on the far side of the island!

There’s good reason this race has earned the nickname Diagonale des Fous. More than in any other ultra you’ve run, you will find yourself questioning your sanity as you climb another towering peak and descend into yet another yawning chasm. Your quads will scream in agony, and your brain will battle the sleep monsters more than ever before. But the sweetness, oh the sweetness of that finish line… it will be the best you’ll ever experience – you’ll have conquered the most gruelling 100 miler out there, and you’ll have the medal and the memories to prove it.

About the author: Linda Doke is a South African Athlete who has been running ultras for +27 years. She is an ambassador for Salomon, 30 South Eyewear and a well respected trail running coach. Linda ran Grand Raid Réunion in 2012 and finished in the top 10 women.

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