In a season of devastating wildfires, where could it burn next?

When the rampaging Valley fire branched off early last Sunday, sending flames roaring into the Geysers area of northeastern Sonoma County, the stage was set for another catastrophe on par with a 1964 inferno that still burns in local memory for all who felt its devilish wrath.

Similar to the Hanly fire, the southwestern flank of the Valley conflagration advanced through The Geysers last Sunday with the aid of strong winds and bone-dry vegetation. When it became apparent the blaze was intent on cresting the Mayacmas Mountains and sweeping farther into Sonoma County, Cal Fire dispatched about 20 firefighters to the mountain to make a stand.

Officials said the small force was all they could muster, given the amount of resources needed to battle flames threatening lives and property in Lake County. But if the Mayacmas crew failed in its mission, the potential existed for the Valley fire to dramatically expand in Sonoma County, with flames racing toward Healdsburg and other communities.

“We understood if we didn’t get it stopped, it would continue to march down Pine Flat Road,” said Cal Fire Battalion Chief Marshall Turbeville, who led part of the team on the mountain.

The Valley fire, which as of Sunday had consumed 75,700 acres and was 69 percent contained, is a searing reminder of the fire dangers that exist in Sonoma County, which just like its neighbor is suffering after four years of a drought that has considerably amped up the threat level.

“It’s not a matter of ‘if,’ it’s ‘when,’?” Turbeville said.

He spoke those words three days before the Valley fire exploded. Turbeville had driven up steep and winding Pine Flat Road to survey the remains of a home that was destroyed in a 2004 Geysers fire and to discuss present and future fire risks in the area.

He predicted the region’s next major conflagration would be a “horrific event” lasting about four to six hours. He said it would be “one bad afternoon,” which is also the title of a presentation the battalion chief gives about blazes.

While the massive fire that broke out in Lake County three days later has lasted considerably longer than a few hours, the worst damage and loss of life appears to have occurred that first afternoon, as Turbeville said it would.

A similar scenario could easily play out in Sonoma County, fire officials say.

Santa Rosa’s eastern hills are one focus of concern, in particular the exclusive Alta Vista neighborhood and adjacent Montecito Heights, Hidden Valley and Brush Creek neighborhoods. As the basis for their concern, officials cite the 1991 Oakland Hills firestorm that burned across 1,520 acres, killed 25 people and destroyed 2,843 single-family dwellings.

“We have a very clear potential for an Oakland Hills fire,” said Jack Piccinini, a Santa Rosa fire battalion chief. “It’s homes built in the hills, surrounded by eucalyptus, oak and cypress. The roads are narrow.”

Other areas drawing heightened attention in Sonoma County include the Mayacmas Mountains along the eastern edge of Sonoma Valley, the grasslands northwest of Petaluma, populated areas north of Santa Rosa in the Riebli-Wallace neighborhood, pockets in west Sonoma County where sudden oak death has been prevalent and the Palomino Lakes community in Cloverdale.

Fire officials stressed that they aren’t trying to be alarmist by naming places that cause them particular worry, or to make residents who live in those areas feel more vulnerable than they may already. The reality is that after a fourth year of drought, there are few places in Sonoma County that are immune to fire danger.

“The whole county is a tinderbox,” said Steve Baxman, chief of the Monte Rio Fire Department.

Still, there are areas in Sonoma County where fire danger is more readily apparent. Almost all are situated in heavily wooded and steep terrain. Those that abut urban landscapes are the greatest concern.

A prime example are the neighborhoods in east Santa Rosa above the Flamingo Resort and Spa and the Santa Rosa Rural Cemetery. Dozens of large homes dot the hilly and wooded terrain, which is accessed by narrow and twisty roads resembling a figure eight.

During a recent hot spell, Murat Uraz felt a sudden unease as he stood on the porch of his Alta Vista Court home overlooking Santa Rosa and observed the city sweltering in the shimmering heat.

Uraz said he made a mental note of what he would take with him if he had to flee a fire in the area. Besides his wife, of course, the list included a hard drive containing family photos, credit cards, passports and Bijou, the couple’s beagle mix.

“When I looked at the valley from my front porch, it scared me,” said Uraz, an engineer and CEO of Arrive Technologies.

To mitigate the risk, Uraz pruned limbs of Douglas firs overhanging his house.

“What else can we do?” he said.

On May 18, the North Bay Incident Management Team, comprising emergency responders from Sonoma, Marin and Napa counties, focused on Santa Rosa’s eastern hill neighborhoods for a simulation aimed at improving the initial response to blazes on steep and wooded terrain populated with people and homes. The scenario was a 57-acre fire breaking out near water tanks on Del Rosa Avenue and racing up the hill, burning homes and forcing evacuations.

The simulation, which did not involve personnel or equipment being sent into the neighborhood, was overseen at a command post established at Santa Rosa Fire Department’s training facility on West College Avenue.

“We have plans in place, but we just needed to check in with ourselves to do some fine-tuning,” Piccinini said.

A woman who recently moved into a home on Del Rosa Avenue said she and her husband didn’t realize the magnitude of the fire danger until their insurance company abruptly canceled their homeowner policy, citing the home’s location in a fire zone. The woman asked that she not be identified out of concern the new policy the couple obtained might also be canceled.

“Had we been informed of all these dangers, we probably wouldn’t have bought the house,” she said.

Such concerns have been magnified across the region as a result of the Valley fire, which already is the sixth most destructive in state history.

Dispatch records show the fire crossed into Sonoma County at 4 a.m. last Sunday at The Geysers. The flames swept across Calpine Corp.’s geothermal complex and by 1 p.m. were threatening to crest the mountain and charge toward Healdsburg.

Turbeville, who grew up in Geyserville and who followed in his father’s footsteps as chief of the fire department there, knew the fire posed an extraordinary threat. He raced up Pine Flat Road in his pickup and met reinforcements at the gate to the geothermal complex.

Santa Rosa Fire Battalion Chief Scott Westrope led those reinforcements, crews on six engines from Sonoma and Marin counties. He took half the team to battle flames closing in on a geothermal plant. Turbeville headed off with the other half, a crew that included firefighters from Geyserville, Rohnert Park,Valley Ford, Cloverdale and Marin County, to try and hold the line at Pine Flat.

Turbeville and his crew immediately were tested by a 50-acre spot fire coming over the ridge toward the road. The crew lit backfires for hours on end to keep the blaze from crossing the narrow road and dropping down the steep canyon. From overhead, air tankers dropped loads of flame retardant.

The strategy worked to stop the fire’s advance. Westrope said Turbeville’s knowledge of the Geysers area made the difference in what could have been a terrible turn in the event.

“They kept it from going over the hill and backing down into Sonoma County,” Westrope said.

Turbeville was modest about his efforts and those of his team.

“We just did what we needed to do,” he said.

They likely will be called upon to do it again.

High on Pine Flat Road, southwest of where the Valley fire crept, a dense undergrowth flourishes in stands of dead trees, testifying to nature’s ability to bounce back from fire. The area was part of the 2004 Geysers fire that consumed 12,525 acres. The more recent McCabe fire, which started during Thanksgiving week in 2013, charred more than 3,505 acres.

“It’s like a jungle out there. We’ve got more ground fuels than we did in ’04,” said Rody Jonas, whose home off Pine Flat Road has survived recent wildland blazes.

Elsewhere in Sonoma County, the sight of tinder-dry vegetation accumulating in places where it poses a potential threat conjures the age-old debate of whether the modern era of fire prevention and suppression has made matters worse.

“We’ve been good at putting fires out the last 100 years,” Turbeville said. “There are people who say that’s catching up to us, particularly due to the drought and long-term weather conditions. We have fires that are burning much more intensely and spreading much more rapidly than if fire ran across the landscape on a regular basis.”

Across the American West, it’s shaping up to be a record fire season, with major conflagrations resulting in the loss of life and property and stretching firefighting resources to its limits. In addition to the Valley fire, the Wragg fire, in Napa County in late July and August, and the Rocky fire, in Lake, Yolo and Colusa counties, scorched nearly 80,000 acres combined.

September and October are the height of fire season in California, when warm temperatures, low humidity and strong winds - coupled in recent years with drought - foment ideal conditions for small blazes to morph quickly into out-of-control monsters.

“The potential is there,” said Will Horne, chief of the Mayacamas Volunteer Fire Department. “We’re very vigilant. Any kind of problem, we get right out.”

Horne said fire conditions on the mountain east of Glen Ellen to the Napa County line are the worst he’s seen in nearly six decades in fire services. The department’s eight volunteer firefighters are the first responders in an area of roughly 30 square miles, with a population of about 600.

The landscape includes thick stands of Douglas fir, oak and redwood, as well as thousands of dead knobcone pines that were planted in the aftermath of the 1964 Nunn’s Canyon and Hanly fires to help with erosion control. The pines have reached the end of their lifespans, according to Horne. He said when the trees catch fire, they “blow up like a Molotov cocktail being thrown in the street.”

The conditions are dangerously similar to those that existed when the Hanly and Nunn’s Canyon fires broke out on the same day - Sept. 19 - a half-century ago.

The Hanly fire, started by a deer hunter who flicked his cigarette behind a roadside tavern near Mount Saint Helena, marched from Calistoga all the way to Santa Rosa before being stopped within yards of the former county hospital on Chanate Road. The fire burned across 52,700 acres, making it Sonoma County’s largest - and the fourth-largest on the North Coast - in the past 50 years.

The county’s population has grown exponentially since then, exposing more people and structures to fire danger.

A 2011 study found that about 12,600 buildings in Sonoma County were in areas with “high and very high risk of wildfires,” with an estimated replacement value of $4.8 billion.

The study identified four “historic wildfire corridors,” including the Hanly fire area; Sonoma Valley, scene of the Cavedale fires in 1925 and 1966; The Geysers, with fires in 1988, 1999 and 2004 that covered a total of 22,000 acres; and the Guerneville area, which was hit by major fires in 1923 and 1961, the latter burning 5,800 acres, 18 homes and $500,000 worth of timber.

In Santa Rosa, about one-fourth of the city’s residents live within four moderate-, high- and very-high-severity fire zones, mostly hilly, wooded areas all east of Highway 101. Two of the zones bracket Annadel State Park: one of them east of Summerfield Road, the other along Highway 12, including parts of Oakmont.

The largest zone covers a broad swath of northeast Santa Rosa, including all of Fountaingrove and the Chanate Road, Hidden Valley and Brush Creek areas down to Highway 12. The zone incorporates the area threatened by the Hanly fire.

The report was written prior to four years of punishing drought, which has rewritten the book on fire hazards in Sonoma County and across California.

“We’re seeing fire conditions we’ve never seen before, so much of this may be out the window,” Sonoma Valley Fire Chief Mark Freeman said.

He identified Sonoma Mountain as another area of concern for firefighters. A wildfire there could threaten a number of communities, including Glen Ellen, Sobre Vista and Eldridge - home of the Sonoma Developmental Center.

Baxman, with Monte Rio Fire, said areas of concern in west and northwest Sonoma County include pockets along Hauser Bridge Road between Tin Barn Road and Seaview Road in the Cazadero area, and between Monte Rio and Occidental along Beedle Road. He said both areas have high concentrations of trees that succumbed to sudden oak death.

Coastal parks also are vulnerable to fires because of an abundance of high grasses and strong winds blowing in from the ocean, Baxman said.

“Something that starts there could take off racing,” he said.

For complete wildfire coverage go to: www.pressdemocrat.com/wildfire

Staff Writer Randi Rossmann contributed to this report. You can reach Staff Writer Derek Moore at 521-5336 or derek.moore@pressdemocrat.com. On Twitter @deadlinederek.