UPDATE: California Highway Patrol reports Highway 101 in both directions south of Los Alamos is open.
The cause of the fire is under investigation.
Santa Barbara County firefighters are responding to a vegetation fire south of Los Alamos Tuesday.
The fire broke out at about 1:40 p.m. on the northbound side of Highway 101 near Alisos Canyon Road.
Fire officials say the fire is less than one acre.
California Highway Patrol is working on closing a portion of Highway 101 in the area as fire crews work to control the fire.
This is a developing story and will be updated when new information becomes available.