See the list of areas impacted here.
RELATED: Are you ready for a blackout? Here's how to prepare if PG&E cuts electricity during high wind, fire danger
PG&E has alerted customers in 30 counties they may lose power. The proactive outage alert covers every Bay Area county, except San Francisco and Marin County. PG&E says it will shut off power to parts of Napa County, as well as the cities of Lafayette, Moraga and Orinda if the weather doesn't change.
Originally Caltrans planned for both the Caldecott and Devil's Slide tunnel's to be closed during the outage, but by Tuesday evening they announced that PG&E had provided back up generators to keep the tunnels open.
A Red Flag Warning is in effect for all Bay Area counties except San Francisco. The warning goes into effect tomorrow at 5 a.m. to Thursday at 5 p.m.. Gusts are expected to reach 45-55 mph and humidity will reach 10-20 percent.
According to the Lafayette Police Department, they were notified by PG&E that they will be conducting a shutoff in Moraga, Orinda and Lafayette from Wednesday 4:00 a.m. to Thursday 12:00 p.m. If weather conditions do not change they will begin de-energizing the power lines at 12:01 a.m. on Wednesday.
This shutoff is expected to impact 6,516 in Moraga and 7,500 in Lafayette.
The main period of weather risk is early Wednesday morning through Thursday midday. The dry, windy weather pattern is expected to reach from the northern portions of PG&E's service territory and down through the Sacramento Valley before spreading into the central areas of the state including most of the Bay Area.
PG&E said they will continue to monitor weather conditions and provide updates to customers. However, they announced that as of 10 a.m. Tuesday, they are experiencing high volume of traffic to their website, which is causing delays accessing their outage-related web pages.
PG&E launched a website in August to warn customers about pre-emptive shutoffs. Go here to learn more.
LIST: Schools impacted by potential PG&E power shutoff
When PG&E first announced that they do power shutoffs on Wednesday, in Santa Rosa, residents knew the inevitable would become Wednesday's reality.
"There is a significant increase in firefighters present," said Pail Lowenthal, Assistant Fire Marshal with the Santa Rosa Fire Department.
The Santa Rosa Fire Department had added four engines with 16 firefighters to boost their presence in the area.
"We have a network of fire cameras that we will be monitoring, we have the ability to activate the emergency alert systems a lot earlier and quicker today locally than we did in October 2017," added Lowenthal.
RELATED: PG&E Power Outages: How to find out they are coming and deal when they do
Residents who are not in the safety power shut off area may also experience power loss if power lines are damaged by these strong winds.
PG&E is warning customers that power won't be restored immediately once the winds have subsided.
Ken Baldwin is a Santa Rosa resident who says there are still many trees near power lines that should have been cut down. Instead, they have markings on them.
"I understand that catastrophe happens but you would think than in two years they would have been able to make more progress than just drive around and mark things," said Baldwin.
Mae Matos was filling up her car and told us she's prepared.
"My father-in-law did it this morning and reminded me to do this," said Matos.
Now, it's only a matter of time before the lights go out at Makers Market on 1st Street in Napa.
Salesperson Allie Huffman said, "It affects the tourist industry, it affects locals, because if they can't get gas and I can't get the lights on how can I fuel my business and get customers in?"
Napa resident Tom Rossi said, "They want to jack us around with all this power outage and other crap we've got."
Rossi is fuming as he waits in line at the Arco station on Soscol Avenue. He's not the only one taking precautions. The lines to fill up are out to the street here.
Napa resident Kari Fasteen said, "I know there's going to be a power outage and the pumps aren't gonna be working supposedly after midnight so that's why I'm sitting here."
Thousands of students will also be affected by the power outage-- Napa Valley Unified School District has decided to close all of its schools Wednesday and Thursday.
Working parents are scrambling to find childcare coverage for those days.
Eunice Ventura said, "That's going to be tough because my schedule is going to change and my schedule is hectic now it's kind of difficult."
As some residents brace for power outages others are taking a moment to reflect.
It was two years ago Tuesday that the Tubbs Fire tore through Sonoma County-- destroying thousands of homes.
The county and the city of Santa Rosa invited residents to a public gathering Tuesday night in Old Courthouse Square to observe the anniversary of the North Bay fires.
A small gathering, but meaningful with a moment of silence and the ringing of a bell to honor the 24 people who died.
In the South Bay, PG&E said it doesn't anticipate any power outages in San Jose on Tuesday night. However, that is expected to change by Noon on Wednesday.
San Jose's Deputy City Manager, Kip Harkness, said the City is "professionally paranoid." Just one way he's describing the City's approach to the looming Public Safety Power Shutoffs.
You'll recall, 38,000 PG&E customers across Santa Clara County could be impacted.
"We should be prepared for as soon as midnight tonight for the power shutoffs in the area to take place," Harkness warned, during an afternoon press conference.
However, many residents told ABC7 News they weren't sure how to prepare for PSPS.
"I don't even know what to expect," Uma Mamidanna said. "I've never experienced anything like this before. So, we'll see how it goes."
Mamidanna and other South Bay residents rushed to a local Safeway in Almaden Valley on Tuesday evening. The area is under the potential power outage zone.
At one point, much of the store's bottled water was cleared from shelves, and packed into carts next to canned goods, bags of ice and ramen.
"I have whether we have enough or not," resident, Susan Lu admitted. "Just praying God will protect all of us."
On our roads, the City's Department of Transportation estimates there are nearly 100 intersections that could lose signal in the shutoff.
Story Road in East San Jose alone sees more than 30,000 vehicles a day. This means any shutoff, could make for dangerous travel.
PG&E plans to open a Community Resource Center at Avaya Stadium on Wednesday morning.
Three City Resource Centers will also be available to impacted residents.
A release by the City of San Jose explained: The City-run resource centers will be open starting Wednesday, October 9 from 8:00 a.m. to 8:00 p.m. for the duration of the event.
Residents will have access to information, charging stations for phones and plug-in medical devices, water, and light snacks.
Spanish and Vietnamese interpretation will be available.
However, the City emphasizes that sheltering and medical care will not be provided at the resource centers.
Impacted residents may visit the following locations for assistance:
- Camden Community Center, 3369 Union Ave
- Mayfair Community Center, 2039 Kammerer Ave
- Southside Community Center, 5585 Cottle Rd
"At some level, this is just a power outage, and so, this is not a big deal," Harkness said. "But as people come in, or as the duration increases, we'll be able to scale up or add capacity either at those community centers, or bring additional community centers online to meet the needs of our residents."
As the South Bay braces for PGE's public safety power shutoff, medical facilities throughout the region are getting ready for potential impacts.
"We're going to be opening up our hospital incident command center if we need to," said Santa Clara Valley Medical Center interim hospital director Sanjay Kurani, MD. "We will activate our emergency response plan and we'll make sure that we have capacity as needed for our patients throughout the county."
Some medical providers have been frustrated by what they say has been a lack of timely communication from PG&E, including representatives with Satellite Healthcare, which provides kidney dialysis and related services to more than 4,500 patients across 46 locations in the Bay Area.
"This is a very vulnerable part of our community," said Satellite Healthcare chief medical officer Brigitte Schiller, MD. "We will make sure that patients get dialysis one way or another, but this is not sustainable over a long period of time."
ABC7 News visited Mothers' Milk Bank in San Jose on Tuesday, which is a nonprofit organization providing pasteurized donor human milk to premature and NICU infants across California. They're ready to go with a generator in case their power fails.
"It's important to keep the milk frozen," said Mothers' Milk Bank executive director Jonathan Bautista. "In the event of a power outage, if someone loses their milk in the freezers, they can reach out to the hospitals and the physicians they work with, and request a milk through a prescription."
San Jose State professor and emergency preparedness expert Franny Edwards, PhD, says pharmacies and stores could also be impacted by a power outage.
"They won't have security. They won't have cashiering capability, ATMs won't be available, so preparing ahead is critical," said Edwards. "People need to think today about whether they have a week's supply of the essential medications that they take every day."
In Alameda County there will be approximately 35,000 customers affected. On Tuesday, Governor Gavin Newsom said this shouldn't be a surprise because they knew this for over a year.
Newsom says he's been working with the utility company to prevent shutoffs like the ones we're about to experience.
"We aggressively legislated a stop-gap solution trying to get PG&E out of bankruptcy so they can upgrade their system and have a modernize ability to turn on and off their grid," said Gov. Newsom.
"I would continue to urge PG&E to put the people before the shareholders and that this needs to be about public safety not about cost savings," said Oakland Mayor Libby Schaaf.
The emergency of severe fire danger will affect every single Bay Area County with the exception of San Francisco.
One of the affected areas is Oakland Hills. Resident Sarah Jane Seideman said, "I'm just charging all of my phone chargers and I have an extra cellphone at home so I'm hopefully going to use that as our connection to the world and prepare for that."
Someone else who will be affected is Rose Yi. The yogurt business Yi manages will see thousands of dollars in losses. All of their milk and fruit will go bad after midnight.
A Red Flag Warning goes into effect Wednesday at 5 AM to Thursday at 5 PM and the shut-off could last up to five days.
"But there is a possibility that they can restore power sooner and I believe that really depends on when they can get out and inspect lines and make sure they can reenergize those lines that were de-energize," said Oakland Fire Chief, Darin White.
To prevent looting and respond to emergencies every Oakland Police officer is mandated to work during the shut-off.
"We've even assigned our entire investigative team in uniform out on the field. We'll be prepared for emergencies. Your safety is number one to us," said Oakland Police Chief, Anne Kirkpatrick.
In San Mateo County, most of the areas in the PG&E fire zone are south of Highway 92-- all the way to the Coast.
PG&E contractors worked near Highway 92 in San Mateo, trimming trees too close to power lines. PG&E appeared to have a new fire break around its Jefferson substation.
Upscale Emerald Hills, with its expensive homes, was in PG&E's fire zone-- a community with narrow winding roads where strong winds from the northwest sweep down in the afternoons.
The ACE Hassett Hardware Store was the most popular spot in Half Moon Bay, some of its shelves empty by noon. Generators were selling like hotcakes.
But the most noticeable impact may be here at the Tom Lantos Tunnel at Devils Slide on Highway One-- a heavily traveled artery.
The power shutdown will force Caltrans to close the tunnel from noon Wednesday to Thursday afternoon.
For the latest stories about PG&E's Public Safety Power Shutoff go here.
ABC7 News' Luz Pena, Amanda Del Castillo, David Louie, Wayne Freedman, Lisa Amin Gulezian, Laura Anthony and Vic Lee contributed to this report.