Cal Fire said the maps are proactive, to be used in wildland-urban interface building standards for new construction and natural hazard real estate disclosures at the time of sale.

Some cities had fewer acres in the very high risk designation, but most of the region had more high risk acreage.

Cities with first-time fire zone designations include Santa Monica, La Cañada-Flintridge, South Pasadena, Alhambra, Huntington Beach, Laguna Hills, Chino Hills and Rancho Cucamonga.