Red flag warning issued for most of North Bay

A red flag warning of weather conditions increasing the risk of wildfires was issued for most of the North Bay, meaning gusty winds and hot, dry weather conditions are expected starting early Wednesday.

The warning, which the National Weather Service upgraded from a fire weather watch and expanded to cover the North Bay valleys, starts at 5 a.m. Wednesday and lasts through 11 a.m. Friday.

The increased fire risk has prompted Pacific Gas and Electric Co. to consider shutting off power to customers across much of Northern California, including as many as 1,781 customers in Sonoma County beginning Wednesday afternoon through Friday night, PG&E officials said.

The company will likely make the decision on whether to initiate the power shut-off and to what extent by Wednesday morning or early Wednesday afternoon, Mark Quinlan, PG&E’s incident commander, said during a virtual press conference Tuesday evening.

“We really view it as a last resort option and we put a lot of thought and effort and a lot of data analysis into it to make the public safety power shut-offs as small as possible to start with and then as short as possible in duration,” Quinlan said.

The announcement about the expected dangerous fire weather came Tuesday as fire crews closed in on full containment of the Glass fire, which ignited Sept. 27 on the eastern rim of the Napa Valley during a red flag warning and was driven by windblown embers to the eastern edge of Santa Rosa.

Cindy Palmer, a meteorologist with the National Weather Service, said dry Diablo winds from the northeast are forecast to reach 55 mph at the highest North Bay peaks and up to 30 mph lower in the valleys, including over the area where the Glass fire burned.

“We’re looking at extremely dry and gusty winds over the Glass fire,” Palmer said.

As of Monday night, firefighters had reached 97% containment on that blaze, which was holding steady at 67,484 acres charred.

A warming trend that began last weekend is expected to push local high temperatures to the mid-80s to low 90s by Tuesday afternoon, and to the upper 90s by Thursday and Friday, Palmer said.

PG&E on Monday warned nearly 49,000 customers in targeted portions of 21 counties that it may start turning off power as early as Wednesday afternoon to stop the utility’s equipment from sparking another blaze.

New totals provided by PG&E during the Tuesday news briefing put the number of potentially impacted customers at 54,000 across 24 counties.

Nearly a quarter of the customers who received the PG&E warning live in the North Bay, primarily in the mountains near Mount St. Helena. The power cuts could affect 1,781 customers in Sonoma County, 9,230 customers in Napa County and 30 in Lake County, PG&E said Monday night.

In Sonoma County, power may be cut off in areas east of Cloverdale, Asti, Geyserville and Porter Creek near Calistoga Road. Parts of the communities of Kenwood and Glen Ellen also could have electricity turned off, PG&E spokeswoman Deanna Contreras said.

The utility targets areas where hot and windy conditions pose the greatest risk to its equipment sparking dry vegetation.

PG&E could begin shutting off power for Sonoma County customers as early as 6 p.m. Wednesday, PG&E said.

The utility hopes to restore power to most customers within 12 daylight hours after the danger has passed.

The company expects to get an “all-clear” that the fire weather has passed on Friday morning, which will allow them to restore power to most of the customers affected by the power shut-off by 10 p.m. Friday, Quinlan said.

To reduce the number of customers who lose power during extreme fire weather, PG&E has recently installed 58 devices that break up its grid in Sonoma County into smaller sections that can be turned on and off. That explains why some homes may lose power while the lights remain on down the street, Contreras said.

The tactic will help the company keep power on for roughly 12,000 people during the most recent potential planned blackout, Quinlan said.

“It depends on where the device is located on the (distribution) line,” she said. “It could be that two doors down has power and two doors up doesn’t, depending on where they are on the grid.”

Ahead of the critical fire weather conditions, all local Cal Fire units have returned from battling blazes elsewhere in the state, Cal Fire spokesman Tyree Zander said. The 185 personnel assigned to the Glass fire as of Tuesday can also be dispatched to any new fires that ignite in the North Bay, Zander said.

Paul Lowenthal, assistant fire marshal for the Santa Rosa Fire Department, said Tuesday local fire departments in Sonoma County are increasing staffing and working together to form joint strike teams to respond to new starts. At least a dozen additional engine crews will be ready to fight potential fires in Sonoma and neighboring counties, Lowenthal said.

He encouraged residents to make evacuation plans and sign up for county Nixle emergency alerts. Lowenthal also asked residents to limit outdoor activities such as grilling or gardening with electric tools that could ignite dry vegetation.

“Anything that can be done to limit the potential of a spark or wildfire, that’s what we need,” he said.

To look up if your address is included in the potential shut-offs, go to pgealerts.alerts.pge.com/outages/map/?type=forecasted.

To see projected wind gusts hit the play button on the map below:

You can reach Staff Writers Ethan Varian at ethan.varian@pressdemocrat.com or 707-521-5412 and Nashelly Chavez at nashelly.chavez@pressdemocrat.com or 707-521-5203.