This is a long climb where you have to gain a total of 2100 meters of altitude, counting from Ordesa. Nevertheless, I shall consider the real route as starting from Góriz and therefore this section is dedicated to the way to reach this mountain hut.
The walking starts at Ordesa Canyon, in the old parking lot of the National Park. Take the trail east and follow the path on the right after some ten minutes (forking marked by a small statue of the Madonna). For the moment, the whole way up to Góriz is also marked by the red-and-white parallel bands of a long distance trail (GR-11). As you gain altitude along the canyon many waterfalls can be seen and make for great photographs (watch out specially for the "Cascada del Estrecho").
During the high season, Ordesa Canyon can be quite busy with tourists. Do not worry about them. At the end of the canyon they usually turn back after reaching the "Cola de caballo" waterfall. That will be also the first decision point for you. To get on to Góriz there are two possibilities:
1. Follow the GR-11 paint marks. They will take you up by a winding path to the south-east without any technical difficulties.
2. After crossing the last bridge over the river take a small path on your left. It goes up the scree slopes to a rock wall, which can be climbed easily (grade I+) and is equipped with a chain serving as a handrail. Nevertheless, this crossing ("Clavijas de Soaso") is not advisable if you have never done any rock scrambling.
Any one of these options will get you out of the Canyon. Only twenty more minutes or so will suffice to reach Góriz Hut, always following the paint marks of the GR-11.
As you leave the hut, you will have to follow a path leading to the east which goes up the "Barranco de Góriz". At first the path climbs on your right side hand, winding to cross over small rocky barriers that stand amongst green grassy terrain. No more paint marks to be followed here: you have to look for the cairns but this is no difficulty. (Remember that this is the normal route for Monte Perdido. In a normal summer day you might be climbing together with quite a lot of people).
Soon afterwards, the path will change to the other side of the Barranco (your left hand side) to get closer to some small cliffs. From this point on it will be a walk on loose stones, slowly gaining altitude to the east. You will have to cross a five-meter cliff through a short terrace but this is not difficult, there is plenty of place to put your feet on and to grasp with your hands. Just remember that the rock here is really smooth because of the crossing of so many people, and it might get to be a delicate -never dangerous- spot if you get caught by the rain.
At 2980 meters the path reaches the Lago Helado. This is the ice lake where the nearby Grand Cascade of Gavarnie is origined. A nice place to stop for a snack before turning right (south/south-east) and face the final climb of the corridor.
The first step will be to climb a limestone ridge on the west side of the corridor, following the obvious path. This will lead you about half way up the corridor, and afterwards the path will make the rest of the climb through a scree slope that gets steeper every meter you climb. That is the place known as "La Escupidera". It is not really dangerous in summer time, but the upper part (just about the end of the corridor) falls over the north face of Monte Perdido. To make a mistake up there during a winter climb could be deadly, take special care (and adequate equipment) if there is ice or snow in this final part of the climb.
After getting out of the corridor you will see on your left (east) side the Balcón de Pineta and the Lago de Marboré. Only a few meters will be left to reach the summit. Turn right and enjoy the final slope for five more minutes.
Essential GearIf climbing in summer time, no special equipment is required apart from warm clothes and strong boots. In the end of spring and beginning of summer, the higher parts of the mountain might keep some snow on them. In that case consider seriously taking crampons and ice axe. A rope might also be useful.
During the winter always bear in mind that Monte Perdido is the third highest peak in the Pyrenees and a three-thousander. Full winter gear is mandatory in that case, including efficient warm clothes, gloves, harness, crampons, ice axe and rope.