- Time3h 15'
- Vertical rise910 m
- Vertical descent120 m
- Horizontal distance6,2 Km
- Type of journeyMountain Crossing
- Severity of the natural environment3
- Difficulty in movement2
- Amount of effort required3
Access to the small Barrage d'Ossoue reservoir (1840 m) is usually closed to traffic throughout the winter and most of the spring. Sometimes, due to rockfalls, it is also closed in the summer. You should find out beforehand about the condition of the track at Gavarnie tourist information office.
This route, signposted GR 10 long distance footpath throughout, starts at the cabin next to Barrage d'Ossoue (1840 m), where some information boards and arrows indicate the way to follow. Heading northeast follow the plain where the lake is situated, following the river upstream on the left bank. Near the end of the plain, cross the river over a bridge to the right bank. The path leads up the steep slope and becomes more obvious. Ossoue ravine has excavated a deep gorge which the path follows, crossing some faily high areas at some points. This means walkers will have to be careful particularly when the weather is bad or if there is snow on the ground. After clambering over a rocky area where the track has been dug out with pickaxes, the route turns westwards and leads to Grottes Bellevue (2440 m). This is the first group of a number of caves that Henry Russell, an excentric Pyreneean explorer, ordered to be dug in the Vignemale massif. With the Ossoue glacier in sight (crossing with route 30) there is still a steep rise to climb before the valley opens up a little and the slope relents somewhat and, now on gentler terrain, we reach Bayssellance refuge (2654 m).