The town of Briançon in the Hautes-Alpes department extends around the Haute Durance valley, more or less wide and surrounded by the high mountains of the crystalline massif of Pelvoux. This alpine river with a nival regime has its source in the municipality of Montgenèvre at 7,841 ft (2,390 m) above sea level on the slopes of the Anges summit. About 5 miles (8 km) from its source, it is joined by the Clarée, crosses Briançon then receives the Guisane. These two tributaries have a higher flow than the Durance yet are nevertheless less known probably because the Durance valley is an important and ancient communication channel, unlike those in cul-de-sac of the Clarée and Guisane.