Pizzo Cristallina + Passo Grandinagia

Day 1
Ossasco - Capanna Cristallina
T2-T3, 1200m ascent, 3h

The weather forecast for this Saturday afternoon had been quite wet, but we get lucky and don't get more than a light drizzle during the three hour ascent from Ossasco to the Capanna Cristallina. The visibility is rarely more than 50m, though. The modern incarnation of the Capanna Cristallina is quite impressive and offers excellent food and whiskeys.

Day 2
Capanna Cristallina - Pizzo Cristallina - Cresta dell'Arzo - Passo Grandiagia - All'Acqua
T4+ / I, 1500m ascent, 2500m descent, 9h45
(without the Bochetta di Formazzora attempt: 200m ascent and 1h30 less)

At the Passo Cristallina, a white sign indicates the start of the otherwise unmarked Pizzo Cristallina ascent route, through the small cirque to the north-west of the summit. The large snow field in the middle of the cirque is still frozen hard and quite slippery in the early morning, so we mostly use the loose rocks along the southern edge of the snow instead. From an altitude of ca. 2750m, there is a visible path (marked with cairns) through streep scree all the way to the Cristallina summit, which strangely has two separate log books on the summit. (T4)
The Rifugio Camosci sits just below the summit. Up to four people can sleep overnight in the very tidy and well-equipped bivouac.

We descent back the way we came and then follow the marked hiking path descending towards Robiei. Below the Lago Bianco, we join the white-blue-white marked path over the Cresta dell'Arzo and start climbing again. The nice and not particularly demanding path (T4-) is somewhat stained by the infrastructure of the different surrounding reservoirs.

There used to be a path from the Cresta dell'Arzo to the Bochetta di Formazzora, but this is no longer marked on the map. Since several hiking signposts still mention the Bochetta di Formazzora, we assume that the route will still be passable. From P. 2447, a first marking has been erased, but afterwards the route is again easy to reconstruct thanks to many cairns and old white-red-white markings. The wild path (T4-) traverses west through a spectacular landscape, until it is directly above the remains of a glacier. Suddenly, there are no more cairns or other markings. On the other side of the glacier, we can spot one big white-red-white marking in the middle of what seems like a vertical rock face. Apparently there used to be a path here across the glacier (maybe with ladders on the other side?). I presume that as the glacier sank lower and lower, the path became too difficult to maintain and was abandoned. Probably it is still possible to get across somehow, but that will certainly increase the difficulty significantly (see e.g. Zaza's report). We decide to retreat to the Lago dei Cavagnöö instead.
This detour was quite spectacular and certainly not a waste of time, but it should be emphasised that in spite of several signposts mentioning the Bochetta di Formazzora, the former path between Cresta dell'Arzo and the Bochetta is no longer usable.

Another old path that is no longer part of the official hiking path network, is the Passo Grandinagia. At least this route is still almost continuously marked on the map and there is an obvious white sign directly at the start of the route at the northern end of the Cavagnöö dam. Cairns and old white-red-white markings (later on also some newer blue markings) show the way as the path zigzags up through a mix of rocky steps and grassy terraces. An altitude of almost 2600m is gained, but 100m of that is immediately lost again. The descent is very steep but mostly on a good path, except for one three metre long down-scramble. At the bottom of the descent, a strip of steep, hard snow blocks the path. It's strongly advisable to use crampons and/or an ice axe here (even if it's just for 10 metres) or to completely avoid the snow by descending all the way to the bottom of the snow slide, as Felix did. It's rather surprising to find such a dangerous snow slide across a marked (albeit unofficially) hiking path as late in the season as this. Maybe this is exactly the reason why the Passo Grandinagia is no longer part of the official hiking path network?
In the small plain around P. 2507, large blue arrows highlight that the most obvious way out (the Bochetta Cavagnolo) is not a feasible route, and that you have to turn left towards the Passo Grandinagia instead. The sand and screen on the final ascent to the Passo Grandinagia looks incredibly steep from a distance, but as you get closer, it turns out to be much easier than feared. The path on the other side, going down towards San Giacomo, is initially surprisingly comfortable. This changes abruptly when the boulder field to the north of the Pizzo San Giacomo is reached. For some 600m, there is no visible path and you have to fight your way through the rocks, which takes time and energy. After we've finally reached the grass around San Giacomo, the remaining descent to All'Acqua is quick and easy.
All in all, the difficulties on the Passo Grandinagia don't exceed T4, but be particularly careful with the steep snow field!