For the fourth time in the last six weeks, PG&E is advising tens of thousands of customers scattered across Northern California that they may have their power turned off due to high winds and very low humidity.
The state’s largest utility said Tuesday it may begin switching off electricity starting Wednesday night to 54,000 customers in 19 counties, a move designed to ensure that the company’s equipment won’t spark wildfires.
Even before that fresh power outage notice sinks in, forecasters for both the utility and the National Weather Service say they are tracking another potential round of ominous, windy fire weather that could sweep the region next Sunday and Monday.
The exact number and geographic extent of Wednesday outages are a moving target, but they are expected to occur mostly in the northern Sierra Nevada foothills and the northern end of the Sacramento Valley.
PG&E said more than 22,000 customers could have their lights turned off in Shasta County, 11,000-plus in Butte County and nearly 8,000 in Tehama County.
In a preliminary list of anticipated outages released Wednesday afternoon, the company indicated about 6,500 Bay Area customers could be affected. About two-thirds of them are in Napa County, in the hills east of the Napa Valley. Outages would also affect higher-elevation areas of Solano and Sonoma and parts of the East Bay Hills in Contra Costa, Alameda and Santa Clara counties.
In its early assessment of the situation, the company says North Bay locations will likely lose power early Thursday and be restored by Friday evening. East Bay locations would also be shut off early Thursday, but could have lights on again late the same night. Blacked-out areas farther north will likely be without power until late Friday.
PG&E’s projected power outage came as the National Weather Service issued the latest in a series of red flag warnings for dangerous fire weather.
The agency says that wide areas of Northern California will see gusty and very dry northerly or northeasterly winds beginning late Wednesday and lasting on and off through Friday morning. Winds are forecast to be strongest Wednesday night into Thursday morning before easing during daylight hours. A second burst of windy weather is expected to set in Thursday night.
If PG&E follows through with the potential shutoff, it will be the fourth the company has executed since early September.
This year’s shutoffs have been much more limited in scope than the sweeping, disruptive blackouts the company imposed last year over huge swaths of its service area.
But this week’s outages are unlikely to be the last this year.
National Weather Service San Francisco Bay Area forecaster Ryan Walbrun said high winds that could start as early as Saturday night and last through Monday could be stronger than the weather this week and cover a wider range.
“That would include, quite frankly, a lot of Northern California,” Walbrun said. “It would of course include the typical North and East Bay hills. But the potential is that this is the kind of event where the wind will actually mix down into the valleys as well, into lower elevations.”
He said that would mean areas like the lower East Bay Hills and the foothills above Santa Rosa, at elevations from 500 to 1,000 feet, might see the kind of potentially dangerous wind gusts usually seen only over much higher terrain.
And the one thing that could significantly reduce the region’s ongoing fire danger â a nice soaking from an autumn storm â is nowhere in sight.
“Of course we don’t expect any rain,” Walbrun said, adding that weather models aren’t showing any sign of a pattern change.
“Looking at the freshest set of models, some of the best models that we have, that run out through Halloween or early November, they’re just not showing any signal for precipitation,” he said. “Not only for the Bay Area, but really a lot of the West Coast stays dry.”
Copyright 2020 KQED