In the 14th century (1310? or 1330?) , the combination of heavy snowmelt , major rainfall and a terrible storm in front of Capbreton accumulated masses of sand on the coast to the point of forming a bar facing the river Adour blocking suddenly the exit in this place . The Adour then rushes north over a width of 400 m , snatching everything in its path, crossing Ondres and the country of Labenne upstream, engulfing the neighboring ponds, absorbing the lake of Hossegor , ravaging the territory of Soustons to finally find in Plecq (now Vieux-Boucau: boucau = “mouth” in Gascon) an outlet on the ocean .
A new port is created : it is Port d'Albret . A secondary arm remains which joins the ocean at Capbreton , but it is impracticable for not the small vessels .
FWIKI