System 1: Pelmo - Nuvolau
The core zone is elongated along a NW-SE direction; it’s bounded to the east by the Boite Valley, to the southwest by the highest part of the Zoldo Valley and by the Fiorentina Valley, to the west-north west by the Codalonga River, to the north by the Falzarego Valley.
It includes distinct mountain groups: the M. Pelmo group, the Formin-Rocchette-Croda da Lago group, the M. Cernera group and the Nuvolau group. The first group lies on SE-NW direction and from south to north it includes the M. Penna (2,169 m) and the isolated massif of the Pelmo whose main peaks are: Cima Pelmo (3,168 m), M. Pelmetto (2,990 m), Cima di Val D’Arcia (2,626 m). This area is physically separated from the Formin-Rocchette-Croda da Lago group, by a lower hill-shaped chain, extending on a N-S direction (Col della Puina 2,254 m, Col Roan 2080). The second group is composed from south to north, by the Rocchetta Chain, which is elongated on an E-W direction, and whose main peaks are La Rocchetta (2,469 m) and the Becco di Mezzodì (2,603 m), the M. Formin (2,657 m) with its famous highland plateau and the Croda da Lago (2,701 m) that includes the Cima Ambrizola (2,715 m), both elongated on a N-S direction. The Rio dei Loschi, the Forcella Giau and the Rio Mondeval separate westward this area from the M. Cernera group. The most important peaks of this area are: Corvo Alto (2,455 m), M. Cernera (2,657 m), M. Verdal (2,491 m), Col Piombin (2,313 m), P.ta di Zonia (2,282 m). Northward the Giau Pass signs the beginning of the Nuvolau group whose main peaks are La Gusela (2,595 m) and the Nuvolao (2,574 m).