The Governor of California Jerry Brown declared a state of emergency in San Diego County on Thursday where nine wildfires are burning.
The occupants of more than 15,000 homes and businesses have been told to evacuate, as well as personnel at a nuclear power plant and a military base.
Television images showed several homes in flames, with thick black smoke filling the sky and drifting over the Pacific Ocean. In Carlsbad at least eight residences, one apartment building, and two businesses burned to the ground.
The fires are being fanned by strong winds and come in the midst of record temperatures and one of the state's worst ever droughts.
Authorities were growing increasingly concerned about a fresh blaze that broke out in San Marcos, where thousands of residents and students at a California State University campus were ordered to leave.
California Governor Jerry Brown declared a state of emergency to free up resources, saying he had secured a grant from the Federal Emergency Management Agency to help aid local firefighting efforts.
More than 2300 customers in the Carlsbad area were without electricity and schools in the San Diego Unified School district and other nearby districts cancelled classes.