A cigarette, a car backfire: Small sparks can make big fires

Authorities say just about anything could have started any one of the wildfires now tearing through Northern California.

Fire officials have not yet determined the cause of any of the 17 major fires burning north of San Francisco. They say anything from a carelessly discarded cigarette, a downed power line, a car's backfire or a chainsaw's pull could all be a possible ignition source.

California Department of Forestry and Fire Protection Director Ken Pimlott says investigators are on scene, but firefighters are concentrating most of their efforts on rescues and evacuations.

None of the major fires have been contained. Lines are being dug to slow the advance of fires in anticipation of winds arriving. They're spread over a 200-mile region from Napa to Redding.