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From the little parking you can see the col of red ground, it's the col of Pandebano (1212m, 15 min). In the col you can see after a few of meters the little houses of Majada de Terenosa (and the mountain hut of Terenosa) where the little path arrive. Before the huts you must leave the route of the refuge of Urriellu and turn to the southeast (left side). The wide corridor to the visible col in the upper side is the "Canal de las Moñas" indicated with a few of cairns of stones. In a little path in zig-zag continous you arrive to the col near the Majada de las Moñas (1h30min) where you must to search in the left side the ruins of the huts of Las Moñas (only one hut has the roof for shelter).
In the ruins you must turn to the west following the cairns bordering the hillside up to another little col with a great view of the village of Bulnes and the gorge in the below side. In this point the new turn to the left side (north) is evident. The first view of the Picu Urriellu north face in the right side is exciting but the route goes to left searching the little gap in the wall of Horcada de Camburero. After the gap you must descend a few of meters to the col of Camburero. The last 400 meters of slope are waiting in front (to the right side you can see the little path in the hillside to the refuge of Urriellu). It's the hardest part of the route, a long zig-zag among the rocks in a little serpent path to reach a coulouir between the rock walls. The final coulouir is a little exposed with snow but the first meters of the ramp are not complicated. Near of the summit a little channel (not chimney) of grade I (with the use of the hands but very easy) go to the final ridge (50 meters, not exposed). Bordering the left side (the right side it's a little exposed to the south face) you arrive to the summit with a glorious view of the east and north faces of Picu Urriellu and the summits of the Central Massif of Picos de Europa (2444m, 3h30min-4h). The summit of this mountain it's really an spectacular place to rest before the descent for the same route.
In winter generally is necessary the use of crampons and ice-axe, specially in the final coulouir to the summit.