[UPDATE 11:40 a.m.]: All southbound Highway 101 lanes have been reopened, according to the California Highway Patrol. The original story follows:
Caltrans announced that the southbound Highway 101 near Gaviota, in the area of the Arroyo Hondo Bridge, is closed, following an incident with an overturned big-rig truck that took place this Thursday morning. Drivers are being detoured to Highway 154 between Santa Barbara and Santa Ynez, and the northbound lane of the 101 remains open, according to an alert from Caltrans.