Flames from a driftwood burn ignited a 3 1/2-acre grass fire Thursday morning between Highway 1 and the ocean, just north of Jenner.

Cal Fire Battalion Chief Marshal Tuberville said the burn, which is aimed at reducing the accumulation of driftwood on the beach to discourage summer camp fires, began at 9 a.m.

But later in the morning, a strong wind began spreading the flames.

"For about 15 to 20 minutes wind picked up and bent the flames to make contact with vegetation," said Tuberville, adding that additional firefighting resources were called in to prevent the flames from crossing the highway.

The fire was contained by 12:30 p.m., within an hour of additional firefighters arriving at the scene.