In studying last year's destructive Witch Creek Wildfire in San Diego County, the Institute for Business and Home Safety, an arm of the insurance industry, found that flying embers caused the most damage to homes rather than direct contact with the wildfire itself.
"Embers, remember, are burning items, fire brands that are fed by oxygen. And the Santa Ana Winds are oxygen," said Julie Rochman, from the Institute for Business and Home Safety.
An animation by the Institute shows how easy it is for embers to cause widespread destruction. A wooden jungle gym catches on fire, which then sets the whole home ablaze or embers get into the gutters and underneath the roof openings.
"Where that single house survived, without exception, it's because the homeowners had taken effective loss prevention steps. Their windows, their siding, their roofs, their defensible space, their vegetation," said Rochman.
Those homes had ignition-resistant materials. While California just began requiring all new homes in fire prone areas be built with ignition-resistant materials, there are millions not subjected to the new codes.
The Institute just published a guide spelling out how owners of older homes can incorporate those safety measures. Some are expensive, but some are not.
The group points to entire neighborhoods in San Diego County built using ignition-resistant materials, and not one burned.
The study also has a message to developers: homes built at least 45 feet apart were more likely to survive a fire and those built 15 feet or less apart, did not.
CALFIRE says it has known all along residents and home builders can do their part to help firefighters.
"We don't have to have as much fire trucks go out. We don't endanger our people so often. And they're able to put the fire out rather than protect the houses," Dave Hillman, from CALFIRE.
Still, getting Californians to spend the time and money to protect their homes is another challenge.