Orsières–Champex–Chamonix. 55 km and 3,500 m D+. The perfect way into the UTMB circuit. Technical, demanding, and set against the best alpine scenery going. The OCC is the bridge between a one-day ultra and a two-day one.
The numbers
| Metric | Value |
|---|---|
| Distance | 55 km |
| Elevation gain (D+) | 3,500 m |
| Highest point | 2,215 m |
| Aid stations | 6 main ones |
| Cut-off | 13-14 hr |
A course in two halves
Phase 1: KM 0-30 — The long, steady climb
Elevation: +2,000 m up to the Col de la Forclaz (1,527 m). Well-marked forest track underfoot. Moderate gradients of 6-8%. This segment matters psychologically: the first 30 km leave a lot of runners feeling great when in truth the race hasn't started yet.
Phase 2: KM 30-55 — Technical descent into Chamonix
Elevation: +1,500 m / -2,800 m. Rapid changes in elevation, loose rock and gradients of up to 15%. This is where runners go down, concentration having slipped after 30 km of accumulated fatigue.
The key climbs
- Col de la Forclaz (km 15): the first crux.
- Col du Grand Ferret (km 30, 2,215 m): the crossing from Switzerland into Italy.
- The descent to Chamonix (km 30-55): technically the toughest segment of the race.
Fuelling for 9-13 hours
- First 4 hours: 250 kcal per hour.
- Hours 4-9: 350 kcal per hour.
- The closing hours: whatever you can stomach.
Kit
- Down jacket (the Alps are unpredictable).
- Trail shoes with proper grip.
- Poles recommended.
- Basic first-aid kit.
Reference times
| Level | Estimated time |
|---|---|
| Elite | 7 hr – 8 hr |
| Advanced | 9 hr – 11 hr |
| Amateur | 11 hr – 13 hr |
The bottom line
The OCC is the ideal way to get the measure of the UTMB circuit without committing to 40-plus hours on your feet. It is technically demanding, but far easier to handle emotionally than the longer ultras.