Gains on Walbridge fire containment in Sonoma County allow crews to focus on interior burn areas

Fire crews have made substantial progress surrounding the nearly 55,000-acre Walbridge fire, with Cal Fire on Monday night reporting 70% containment of the wildfire in the hills of northwestern Sonoma County.

Work performed over the last week by a still-growing force of ground crews has enabled all but an estimated 774 residents evacuated closest to the fire to return home, as well, Sonoma County Sheriff’s Sgt. Juan Valencia said.

Fire officials cautioned a long road still lay ahead before the blaze could be deemed completely out. Firefighters have focused so far on preventing flames from spreading further into the landscape, and are now turning their attention to the interior of the burn zone.

It could take weeks, or even months, before smoldering stumps and flames skunking around in dense forest are all discovered and sufficiently doused so they no longer present a risk of igniting new blazes, officials said.

Some remaining hot spots could continue to pose a threat until winter rains fall, said Cal Fire Battalion Chief Marshal Turbeville, operations branch director for the Sonoma County side of the LNU Lightning Complex fires.

“This is a real forest fire,” Turbeville said. “This is a timber fire, not 100% of it, but a lot of the southern district. This is going to smolder and continue to burn for a while, until we can get everywhere.”

Redwood stands and other wooded areas can retain heat in their stumps and roots for weeks, smoldering and waiting for the right draft or blast of oxygen to get going, Cal Fire Division Chief Ben Nicholls said. Fire can travel through the roots, too.

Those parts of the trees need to be dug out and flames completely extinguished so there’s no chance of escape, he said.

Also, there may be areas in the burn zone where fire is still active that haven’t burned for 80 years and have accumulated so much fuel they “are going to take longer to burn down,” Nicholls said, especially in those densely forested, southern areas of the inferno’s perimeter “where you’re going to see fire for an extended period.”

Additionally, there are patches of unburned vegetation within the fire scar that still could go up in flames, or places that have burned, but with less intensity or consumption than others, Turbeville said.

“That’s the tricky thing about a wildfire: It’s not like a binary event, where it either burned or didn’t burn,” he said.

Turbeville recalled how firefighters were called in February to a site off Geysers Road near Geyser Peak that was still smoldering after last October’s Kincade fire, only to have to go back again in what he thought was July.

The Walbridge, part of the 586-square-mile LNU Lightning Complex, erupted amid a dry lightning siege that sparked hundreds of wildfires around California in mid-August, including almost a dozen in the North Bay and North Coast area, many of which burned together.

Since Aug. 15, Cal Fire said Monday there have been nearly 14,000 recorded lightning strikes statewide and more than 875 new wildfires, burning more than 1.46 million acres and destroying 2,800 structures.

The scale of the disaster has strained firefighting resources to an unprecedented degree, forcing those that were available, at least on the Walbridge, to pour all of their effort into stopping the advancing edge of the blaze, even as some interior areas burned days earlier would normally have had crews come in to begin mop up, Turbeville said.

Progress on control and containment lines and the continued arrival of resources, including National Guard hand crews that turned up late last week, means firefighters can now start working their way back into the burn zone to do more work, he said.

That’s particularly helpful given weekend forecasts that call for the return of warm, dry weather surpassing 100 degrees in many areas of Sonoma County by Sunday, the National Weather Service said.

Tree fallers have been hard at work taking down hazard trees in advance, as well, to help make the area safer for firefighters and returning residents though all will need to remain vigilant, Cal Fire officials said.

Heavy smoke in the area from the August Complex in the Mendocino National Forest, which has caused extremely poor air quality in Sonoma County but helped calm the Walbridge, will eventually clear out and make it easier for firefighters to spot spiraling smoke from hot spots, Turbeville said.

When people move back into the burn zone, they can be “eyes and ears to help us, too,” he said.

Though emergency officials have “shrunk up” evacuations as much as possible for the time being, there remains areas that are still too dangerous to allow for re-entry, including those where fire remains active and damage assessment teams are still doing their work.

Cal Fire Incident Commander Sean Kavanaugh said at least 126 homes have been found destroyed so far in the Walbridge perimeter, and Turbeville said he did not anticipate that number would rise significantly.

There also are about 220 total destroyed structures, said Tennis Wick, director of Permit Sonoma and acting Emergency Management Director.

Assessment crews have found 468 saved structures, however, “absolutely fantastic,” Wick said.

He said the county has closed its evacuation shelter at the county fairgrounds and expects to demobilize the operations center by Tuesday evening, as it shifts to recovery mode.

Wick said local assistance centers opened in Guerneville and Healdsburg have been assisting residents who have suffered losses to properties register with FEMA. More than 400 already had done so by Monday.

The county put its initial fire-related costs at more than $18 million.

You can reach Staff Writer Mary Callahan at 707-521-5249 or mary.callahan@pressdemocrat.com. On Twitter @MaryCallahanB.