SANTA BARBARA, Calif. - Investigators say the Santa Barbara County wildfire that has scorched more than 30 square kilometres and destroyed dozens of homes was apparently sparked by a power tool used to clear vegetation.

Officials are asking the public for help in identifying who was clearing brush in the area adjacent to the Jesusita Trail on Monday afternoon and Tuesday morning.

The fire has destroyed 31 homes and damaged 47 others. Approximately 30,000 people were forced to flee to safer ground.

All but approximately 350 evacuees had been allowed to return home Sunday, as firefighters had the blaze 55 per cent contained.