A semitruck and trailer were destroyed Monday morning by flames that touched off a grass fire on Highway 101 just south of Buellton, according to the Santa Barbara County Fire Department.

The big-rig with the top of its cab on fire was traveling northbound on Highway 101 near the Nojoqui Grade summit when it was reported to the California Highway Patrol just before 11:40 a.m., according to CHP radio traffic.

Flames were starting to spread to the trailer when it came to a stop on the right shoulder of the highway just north of Old Coast Highway after touching off a grass fire about a quarter-mile south.

When firefighters arrived a few minutes later, they found the cab fully involved with flames and the trailer starting to burn and ordered a full vegetation fire response, said Capt. Dave Zaniboni of the Santa Barbara County Fire Department.

However, the air support and bulldozer were canceled when the fast attack by firefighters and three engines at the scene were able to hold the wildfire to half an acre of grass and brush.

The semitruck and trailer were completely gutted and a total loss, Zaniboni said, although the trailer was virtually empty, carrying only a few pallets. The driver apparently was uninjured.

Northbound Highway 101 was closed as firefighters battled the blazes, but the fast lane was reopened about 12:15 p.m., according to the CHP, allowing traffic to slowly start moving again.

The burned out big-rig had to be hauled away on a flat-bed truck.

Zaniboni said the cause of the fire is unknown, but both CHP and fire investigators are working on locating the source.

This report was compiled by News Editor Mike Hodgson. He can be reached at mhodgson@leecentralcoastnews.com.