Power Shutoffs Underway In Napa, North Bay Amid Red Flag Warning

NAPA COUNTY, CA — Napa County urged residents to be vigilant as the region headed into red-flag conditions.

The National Weather Service issued a red flag warning for Napa County from 11 p.m. Thursday to 11 p.m. Saturday because of low relative humidity and gusty northerly winds.

"Offshore winds of 25-35 mph with gusts to 45 mph, isolated gusts to 65 mph across the highest terrain and ridgetops in tandem with daytime relative humidity as low as 10 percent will result in critical fire weather conditions Thursday night - Saturday," the National Weather Service said.

In addition to Napa County, much of the greater San Francisco Bay Area and Santa Cruz were also under the red flag warning.

Pacific Gas and Electric Co. warned that some in Napa County may also experience a public safety power shutoff during this fire weather. The potential Public Safety Power Shutoff event could affect approximately 20,000 customers, including 3,101 Napa County customers and another 125 Napa County customers considered "medical baseline."

• RELATED: Public Safety Power Shut Off Underway For Some In NorCal

Customers can check their address online at pge.com/pspsupdates to see if their location is being monitored for a potential safety shutoff.

Red Flag Warning

When a red flag warning is in place, fire danger increases due to warm temperatures, very low humidity, and strong winds. The following activities are strongly discouraged when a red flag warning has been issued:

1. Never mow or trim dry grass during a red flag warning because a power tool could spark on a rock and start a grass fire. It is not recommended even on windy, dry, hot days.
2. No wood or charcoal campfires in forests during periods of high fire danger.
3. Thoroughly extinguish all cigarettes and smoking material.
4. Don’t pull your vehicle over in grass, as it can spark a grass fire. If necessary, pull over on paved roads.
5. Use spark arrestors on portable gasoline-powered equipment to avoid an accidental fire.
6. Properly maintain vehicles to prevent roadside fires caused by sparks or flammable materials from the catalytic converter system.
7. Ensure trailer chains don’t drag on the ground and spark.
8. Shooting of firearms is unsafe during periods of high fire hazards.
9. Use extreme caution with welding or blowtorch projects.
10. Burning plant cuttings on high fire danger days is unsafe.

Public Safety Power Shutoff

The PG&E PSPS website showed that power was proactively turned off in parts of the North Bay, in Napa and Sonoma counties, around 6:45 p.m. Thursday.

Given the forecasted strong northerly winds — up to 70 mph in some areas — and current dry vegetation conditions, PG&E said, advanced notifications were sent to customers—via text, email, and automated phone call—in targeted areas where power may need to be proactively shut off for safety to reduce wildfire risk.

PG&E said the duration and extent of a PSPS depends on the weather in that area. Further, not all customers are affected for the entire period.

PG&E was expected to open dozens of Community Resource Centers in the impacted counties to support customers. See a complete list of CRCs.