This is the shortest stage, crossing the highest pass of the entire Alta Via: the Bocchetta di Caspoggio at almost 3000m. Here you can breathe the air of the highest peaks of the group, perfectly visible from the pass. Due to the retreat of the Caspoggio glacier, crossing it can be difficult. The use of an ice axe and crampons is strongly recommended, especially if you intend to travel this section late in the season when the glaciers are heavily crevassed.
Another option is to take the “high” variant, mostly on glacier, through the eastern Marinelli Pass at 3090m, which requires mountaineering equipment and experience; after the glacier section, you descend to the Fellaria Lake and shortly after to the pastures of the homonymous alpine pasture.
If you have no experience crossing glacial terrain, the accompaniment of a guide is strongly recommended, or it is advised to take the simpler variant which passes through the Fellaria Notch at 2819m (variant). It avoids glacier sections but involves a descent to the Carate Refuge where the detour is found.
The Bignami refuge is located at Alpe Fellaria, one of the highest alpine pastures in the valley still in use.