PG&E considers power shut-offs in the North Bay due to elevated fire risk

Gusting winds and low humidity are forecast to bring elevated wildfire risk in the North Bay late this weekend, as well as the possibility of preemptive power shutdowns early next week for nearly 1,800 Sonoma County households, according to PG&E.

But neither wind nor humidity are expected to be bad enough at the same time to trigger a red flag warning that would usher in extreme fire risk, the National Weather Service said.

The region’s residents should still be alert and watchful, given longer fire seasons each year and the potential for last-minute changes in weather conditions, National Weather Service meteorologist Brian Garcia said.

“This is something where they should be thinking, ‘Oh wow, we always need to be prepared and vigilant,’ “ he said.

Garcia nonetheless provided encouraging news on Friday when he said that updated weather models suggested gusting winds predicted overnight Sunday would coincide with relatively strong humidity levels. The winds are forecast to weaken before Monday, when humidity levels “tank,” he said.

“In terms of relative humidity, it looks like it’s going to stay fairly robust,” Garcia said. “Once we’re north of 30 to 40%, that’s where you kind of start breathing a little easier.”

In addition, Garcia said wind gusts would likely remain at 35 to 40 mph, with the possibility of a single gust or two in the mountains reaching 45 to 50 mph.

“We need to see those gusts happen on a regular-ish basis, or to expect them, to trigger that red flag,” he said. “If we’re just going to see a peak gust of 45-50, and that’s all it’ll be, that’s not enough.”

Meteorologists issue red flag warnings based on a combination of dry fuels, low relative humidity and strong winds. As of Friday, the combined outlook for those factors throughout the weekend was not expected to reach similar severity as in previous red flag events. The last such event in the region in December was in 2017.

PG&E, meanwhile, has posted a power shut-off watch for Monday and Tuesday in 15 counties across the North Bay and Sierra Nevada foothills in the event winds appear strong enough to risk blowing branches or debris into power lines.

PG&E spokeswoman Deanna Contreras said late Friday that no decision had been made yet, but the early projection indicated 1,797 Sonoma County customers might be involved, beginning between 4 a.m. and 6 a.m. on Monday, if the utility goes forward with the shut-off.

A portion of Lake and Napa counties would be affected, as well, she said.

“It’s a dynamic situation,” Contreras said. “It’s fluid, and, as always, the number could change and the scope could change.”

Garcia said residents, even without a red flag warning, should “always have a plan in place.” “It’s important for people to remember that we’re not out of fire season yet. Despite getting that little bit of rain, we’re not quite done. We need more moisture in the soils and vegetation before we can stick a fork in fire season.”

Cal Fire Division Chief Ben Nicholls said Thursday that both ground and air resources remain on hand while fire season persists.

“We’re planning on staffing our stations through Dec. 27, with the idea that we’re not going to see significant fire season-ending rainfall before then,” he said.

You can reach Staff Writer Mary Callahan at 707-521-5249 or mary.callahan@pressdemocrat.com. You can reach Staff Writer Kaylee Tornay at 707-521-5250 or kaylee.tornay@pressdemocrat.com.