It's fire season in Woodside and Portola Valley, two wooded communities that analysis has shown have terrain, prevailing winds and the types and moisture content of vegetation that make for a severe risk of wildfire. Not that far away are raging infernos, driven by low humidity and dry northeasterly winds, that led to a devastating loss of life and property in the North Bay.
An aerial video of the suburban Coffey Park neighborhood in Santa Rosa shows block after block after block of parcels that are now uniformly, and chillingly, the color of ash.
Could such a fire happen here?
"We don't typically get those type of winds, but that doesn't mean that they couldn't happen," Fire Chief Dan Ghiorso of the Woodside Fire Protection District said. "Mother Nature makes her own rules."
"That is a wind-driven fire," the chief said of the fire that destroyed Coffey Park. "There is just too much wind for anybody to do anything about that. The fire's just moving too fast, with way too much heat and the humidity is low. ... It's just so intense that there is no way to stop it."
It's not yet known what happened in Coffey Park, what caused the fire to spread from house to house to house, the chief said. But the Woodside fire district will take what lessons it can from "the nightmare that's been happening up there," he said.
From the inside out
Woodside district Fire Marshal Denise Enea noted that while some 2,000 houses are now gone in Santa Rosa, the trees are still there an indication that the homes may have burned from the inside, that burning embers found a way in.
When an ember is in the outside air, it quickly burns itself out, but when it's inside a house, "it's like getting into a box," Enea said. "It has nowhere to go so it has to burn the box." Embers enter through an airway, which can then serve to funnel air inside to feed the fire. "These houses could have had hundreds or thousand of embers (inside)," she said.
Embers would behave no differently here than there, but the conditions that led to the intensity of the Santa Rosa fires are uncommon here, Enea said.
"The Bay creates a lot of water moisture in the air, as does the ocean and its off-shore breezes, which keep winds blowing from west to east, which is always the saving grace for us," she said. "Ninety percent of the time, that's the wind we have. That's why we're so very very lucky."
The Woodside fire district is most vulnerable in the absence of offshore winds, and when the air is hot and dry. But 50-mph winds are "very very infrequent" here, she said. "When you have that type of weather," she added, "there is no structure that is totally fireproof."
Had the wind come up during the Skeggs fire in mid-September in the hills west of Woodside, "that would have been a game-changer," Chief Ghiorso said.
The destruction of Coffey Park has changed the norm for flatland communities, said Chief Harold Schapelhouman of the Menlo Park Fire Protection District. But the same thing happening in the Menlo Park Fire Protection District has a very low probability, he said.
"You can't say never because that would be a little dangerous to think it could never happen," he said.
Efforts to remove ignitable material from around structures might not have mattered in Santa Rosa, he said. Restaurants, schools, hotels, all burned. As to the possibility that buildings might not have been sufficiently protected against the entry of embers, Chief Schapelhouman noted that the conditions were severe.
With a constant horizontal stream of embers crossing the road at 50 mph, 60 mph, 70 mph, "it's basically raining fire," he said. "What we just saw is really something that hasn't been seen before in an urban environment."
"There's no reality to compare it to," he said. But now that this fire has occurred, an analysis can begin, lessons can be learned, and the state building code may be amended, he said.
A big difference between this fire and the Oakland Hills fire in 1991 is that firefighters in Oakland were familiar with the behavior of fire on hills, he said.
What to do?
"I do think the residents (in the Woodside fire district) are more proactive than many residents throughout the state of California," Chief Ghiorso said. The guidelines for fire safety are well publicized: avoid shake shingles and roofs, protect against the intrusion of embers, remove vegetation that could ignite from around homes, have evacuation plans.
The town of Woodside allocates $100,000 every year to a fund that pays residents up to $2,000 in a 50 percent match to take such steps as removing dead brush and woody debris from around a structure, mowing dry grass, removing limbs from nearby trees and removing some trees altogether.
"Residents are taking fire resistance zones seriously, replacing the roofs at the right time, installing ember-resistant vents," the chief said. "Not everybody is doing it. Slowly but surely we are getting there."
"The tragedy that is happening in Northern California right now, we should learn from it," Enea said. "People should take heed and try to build their houses as fire safe as possible.
"I'm really proud of how we get people signed up for SMC Alert," Enea said. "Lots of people are very inquisitive.
There are district residents who are "very upset" to see the destruction of thousands of homes that are just an hour away, she said. "People are having a hard time with this amount of smoke in their community," she said. "It's very disturbing to them."
Chief Schapelhouman said he's been thinking about the loss of cellphone service that led to Coffey Park residents waking up only when their neighbors were pounding on their doors. "Really what troubles me is the lack of time that people had to get out," he said. "A lot of them weren't notified at all."
A siren would have helped, he said. Cellphones may be more effective, but why not have both, he said. "Notification didn't occur. The notification fell apart. You've got to go back to something that's simple and that will work," he said. "You could have essentially woken the community up."