SAN FRANCISCO (CBS SF) — PG&E said Sunday that an expected high wind event Wednesday could prompt a Public Safety Power Shutoff (PSPS) for some customers in the North Bay, Sierra foothills and North Valley, but that conditions could change substantially over the next three days, making any hard and fast prediction impossible.

“Both the forecast and the scope of the weather event remain very fluid three days ahead of the event,” according to a statement from PG&E Sunday. “At present, projections reflect a possible weather event similar to previous (Public Safety Power Shutoff) events that impacted about 180,000 customers.”

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Later Sunday evening, PG&E said any potential shutoffs would affect approximately 250,000 customers.

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The National Weather Service said Sunday that winds should begin to increase overnight Tuesday, spreading southward over the higher elevations of the North Bay and East Bay around sunrise Wednesday. These north-northeast winds will reach 20 to 30 mph with gusts of 35 to 45 mph expected; local gusts at isolated peaks and ridgetops may approach and possibly exceed 60 mph.

Those winds, combined with humidity readings expected to drop during the day on Wednesday to 10 to 20 percent (and to single-digit percentages in some localized spots), are expected to combine for the kind of fire hazard that prompted a series of PG&E power shutoffs in late October all over the Bay Area, Sierra foothills and other parts of the state.

As of Sunday, portions of the following counties could be affected if PG&E moves forward with a PSPS: Butte, Colusa, El Dorado, Glenn, Lake, Mendocino, Napa, Nevada, Placer, Plumas, Shasta, Sierra, Solano, Sonoma, Sutter, Tehama, Trinity, Yolo and Yuba.

If necessary, the utility plans to notify potentially affected customers starting Monday morning, giving the, 48 hours advance notice.

The wind event could last into Thursday. Parts of Marin County will be affected if a shutoff occurs.

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Andrea Donley of Mill Valley says power shutoffs are becoming painfully routine.

“Food was probably about $150 loss, and having to buy everything that was battery operated costs like $250, so just in that week alone maybe $250-$400,” said Donley of the most recent shutoff. “It sucks, because I’m a single mom.”

PG&E said Sunday that, based on customer feedback and internal reviews of how the October power shutoffs went, that a series of safety and response improvements have been made.

They include expansion and refinement of the PSPS notification system; upgrades to PG&E’s website and call centers to allow handling of much higher levels of traffic; better quality power outage mapping; and improved coordination and communication with PG&E’s government agency partners.

“I don’t find it very positive,” said Ashly Anavisca of Marin City. “Keeping the phones charged at all times that was a really hard thing because we didn’t have any electricity, and no way to communicate.”

At the Cal Fire headquarters in Auburn, equipment has already been mobilized in preparation.

“Winds are always a battle for us,” said Andy Greggerson of Cal Fire.”We just have to take advantage of moving out ahead of it.”

On Monday, the state senate will evaluate power shutoffs and develop a plan of action as part of an oversight hearing. The utility has faced harsh criticism, particularly from small businesses and people with medical needs, for recent shutoffs. The blackouts left many Bay Area communities without power for days at a time last month.

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