This page shows developments through 11:20 p.m. Wednesday. Click here to see the most recent updates.

11:20 p.m. High winds topple trees in Santa Rosa: Firefighters responded to reports of downed trees throughout Santa Rosa “as a result of current high winds” on Wednesday night, according to the Santa Rosa Fire Department. Fire officials urged residents to call 911 if they spot a downed power line or a tree resting on a power line. “Remember to treat all downed power lines as live lines and do not approach or touch,” fire officials said. To report a downed tree in Santa Rosa, officials asked residents to call 707-543-3805.

10:51 p.m. Regional agencies respond to fire in northern Sonoma County: State Sen. Mike McGuire, D-Healdsburg, said on Twitter that the fast-moving fire in a “fairly remote region” in Sonoma County reached 300 acres at around 10:30 p.m. Wednesday. He said wind speeds in the region reached 60 mph and that “significant resources from across the region” were responding to the blaze, including, “Engines, air attack, personnel and bulldozers.”

To read more about the fire, click here for updates.

10:34 p.m. Evacuations issued in response to fire in northern Sonoma County: County officials announced evacuations east of Geyserville in response to the fire lazing in northern Sonoma County. The evacuation order is for Geysers Road to Highway 128, Pine Flat Road, and Red Winery Road, according to the Sonoma County Sheriff’s Office. Authorities urged people in those areas to, “Leave immediately if you are in or near these roads.” Officials also issued an evacuation warning for northern Healdsburg and Geyserville, sheriff’s officials said.

9:55 p.m. Fire reported in northern Sonoma County: A fire was reported in northern Sonoma County along the Lake County line, according to the National Weather Service. The acreage and containment figures were immediately unknown.

8:35 p.m. PG&E plans shut-offs for San Mateo, Kern counties for 1 a.m. Thursday: Roughly 1,000 customer accounts in San Mateo County and 30 customer accounts in Kern County are expected to be impacted, PG&E officials said.

8:30 p.m. PG&E announces outages in 15 counties: PG&E officials said safety shut-offs began in 15 counties in the Sierra foothills and North Bay region on Wednesday, including: Alpine, Amador, Butte, Calaveras, El Dorado, Lake, Mendocino, Napa, Nevada, Placer, Plumas, Sierra, Sonoma, Tehama and Yuba. Roughly 178,000 customer accounts were impacted. In total, roughly 179,000 customer accounts in 17 counties are expected to be impacted in the shut-offs, PG&E officials said.

8:20 p.m. High wind gusts on Mt. St. Helena: Wind gusts reached 69 mph on Mt. St. Helena just after 8 p.m. Wednesday, according to the National Weather Service. Peak winds are expected to continue in the North Bay region through Thursday morning before easing, officials said.

7:50 p.m. Impacted PG&E customer accounts will get power restored before potential weekend shutoff: Customer accounts that were impacted by the shut-offs Wednesday evening will get their power “restored in advance* of any potential PSPS this weekend,” PG&E officials said. Crews will work “safely & quickly as possible after the all-clear,” utility officials said. PG&E’s forecast page indicated that there is an “elevated potential” of a shut-off on Sunday and Monday.

6:49 p.m. PG&E employee attacked: At a press conference Wednesday evening, PG&E President Bill Johnson said an employee of the utility was deliberately attacked in Glenn County earlier that day. “The employee was driving a PG&E vehicle when a projectile hit the front passenger window. Our security team believes that projectile was a pellet from a pellet gun,” said Johnson. He said the employee was not injured and that authorities were investigating the matter. He added that there were “no justification for this sort of violence” as many of its workers live and work in areas affected by the shut-offs as well.

5:59 p.m. Will San Mateo County see shut-offs at 1 a.m. Thursday? PG&E said at a news conference that it is monitoring the weather. “If weather conditions change, favorably - if we can delay the shutdown, we’ll delay the shutdown,” a spokesman said. But, he added, if the winds speed up earlier than expected, the shutoff could come earlier.

5:50 p.m. PG&E president said new shutdown could begin late Saturday: President Bill Johnson said at a news conference that a new forced power outage — this one more widespread than the current one affecting 17 counties — could begin late Saturday.

5:47 p.m. PG&E says power should be restored within 48 hours: Even if damage is found, the utility said customers who lose power in the current outage should have it restored within 48 hours.

5:40 p.m. PG&E is considering power outage this weekend: There will be another round of safety shutoffs this weekend into possibly early next week. PG&E President Bill Johnson said the weekend shut-off will not overlap with the current shut-off. He said power will be restored to customers who have lost it, or are losing it, Wednesday before the new outage begins.

5:35 p.m. Strongest winds of season expected this weekend: PG&E warns it is looking at forecasts of high winds Saturday night until Sunday afternoon that could be the strongest wind event of the season. The utility said the winds could be stronger than those that drove the Wine Country fires in 2017.

5:32 p.m. Gusts of wind have begun — of up to 41 mph: PG&E says that gusty and dry north to northeast winds are starting in Northern California. Some locations are gusting up to 40 mph with low humidity.

5:15 p.m. One town in wine country has its own utility, avoids outage: Healdsburg, a city in Sonoma County, owns its own electric utility, meaning that no businesses, homes or stores will lose power, it said. The town says it is ready to support neighbors who lost power. It owns and obtains electricity from several generation plants in Northern California that run independently from PG&E, the city said.

5:10 p.m. Fire resources gather to prepare: A task force in Contra Costa County has assembled in North Concord in preparation for Wednesday night’s Red Flag weather. “Fire danger remains high overnight,” the Contra Costa County Fire Protection District tweeted.

5:05 p.m. Santa Rosa announces school closures: Four schools — Maria Carrillo High, Rincon Valley Middle, Santa Rosa Accelerated Charter and Hidden Valley Elementary — will close Thursday in response to power outages. These schools were dismissed early on Wednesday afternoon as outages began hitting the area before 3 p.m.

3:48 p.m. Low humidities recorded, Red Flag warning in effect: The National Weather Service says it is observing very low relative humidity values in the North Bay, as it predicted. These dry conditions are expected to persist through Thursday morning. A Red Flag warning is in effect in the North Bay and East Bay through 4 p.m. Thursday.

Very low relative humidity values observed throughout the North Bay at this hour. Critically dry conditions will continue overnight & into Thursday morning as offshore winds increase.



Red Flag Warningcontinues for through 4 pm Thursday. #CAwx #CAFire https://t.co/zw6tVkLpPr pic.twitter.com/c26Q2KKm0e — NWS Bay Area (@NWSBayArea) October 23, 2019

3:33 p.m. Power shut off to customers in Sierra foothills: PG&E’s map system shows outages extended from the Sierra foothills and Northern California coast down to the North Bay.

3:14 p.m. Outages have hit Napa and Sonoma counties: PG&E’s map system shows the outages in various parts of the two counties. According to the map, there are about 875 customers without power near the city of Sonoma and Enchanted Hills. More than 18,000 customers lost power near Hood Mountain Regional Park, Sugarloaf Ridge State Park, Trione-Annadel State Park and Spring Lake Park. About 1,300 customers lost power between Jimtown, Mercuryville and Middletown in Sonoma County.

2:45 p.m. Shut-offs hit Santa Rosa: The Santa Rosa Fire Department said it has started receiving reports of power outages from the Rincon Valley and Oakmont areas.

2:13 p.m. Sonoma County outages to leave 26,845 customers without power: The affected communities include: Annapolis, Cloverdale, Geyserville, Glen Ellen, Guerneville, Healdsburg, Kenwood, Larkfield, Santa Rosa, Sonoma, Stewarts point and Windsor.

2:10 p.m. PG&E says 372 customers to be affected in San Mateo County: The utility said affected communities include: La Honda, Woodside and unincorporated San Mateo County. However, San Mateo County officials said they expected 1,005 addresses to be affected Wednesday morning.

2:08 p.m. Napa County blackouts to total 7,718 customers: PG&E officials said affected communities include: Angwin, Calistoga, Deer Park, Lake Berryessa, Oakville, Pope Valley, Rutherford, St Helena, Napa, Oakville, Rutherford and Yountville.

2:07 p.m. PG&E says 184,345 customers to be affected by shut-off: PG&E officials said in an updated list of affected communities that 184,345 homes and businesses were expected to lose power during the shut-offs. In the Bay Area, officials expected 34,935 customers to be affected in Napa, San Mateo and Sonoma counties.

1:38 p.m. Oakland fire officials warn residents of fire danger: National Weather Service officials issued a red flag warning for the East Bay hills and Oakland starting at noon Wednesday. However, officials said Oakland is not expected to experience any power outages as a result of PG&E shut-offs.

1:22 p.m. Too early to know scope of potential weekend shut-offs, PG&E says: “It’s too early to determine how many people might be affected by any potential event this weekend,” utility spokeswoman Jennifer Robison wrote in an e-mail. “We remain completely focused on the current Public Safety Power Shutoff scheduled for this afternoon and tonight.

12:58 p.m. Residents in high-elevation areas of St. Helena should conserve water: The city of St. Helena in Napa County is asking residents in high-elevation areas, like hillsides, to conserve water during the power shut-offs, so the fixed generators at its pump stations aren’t overtaxed once in use. Erica Ahmann Smithies, Public Works director in St. Helena, said parts of the city could be without power Wednesday as it awaits expected outages by PG&E. “Most of our customers aren’t in high-lying areas, but the ask for conserving water comes from lessons learned two weeks ago,” she said. “Luckily, we were able to get water to residents, but we were without power for more than 48 hours.”

12:01 p.m. Napa County blackouts holding relatively steady: The likely number of shut-offs in Napa County has gone from 7,533 customers to 7,488 homes and businesses, according to PG&E. The affected areas will include portions of Angwin, Calistoga, Deer Park, Lake Berryessa, Oakville, Pope Valley, Rutherford and St Helena.

11:26 a.m. A podcast on another round of PG&E shut-offs (pro tip: charge your phone while listening): Chronicle staff writers J.D. Morris and Mallory Moench discuss what to expect during the shut-offs and answer key questions about what people can do to during the blackouts.

11:19 a.m. Rep. Josh Harder, D-Turlock, slams power shut-offs on House floor: Harder took direct aim at PG&E by noting that some of his constituents already had power cut for days earlier this month and they now face more blackouts. He also referenced company CEO Bill Johnson’s recent comments that outages could continue for the next decade. “I refuse to accept that,” Harder said, according to a transcript of his remarks distributed by his office. “Regular people can’t choose to not pay their bills — and PG&E shouldn’t be able to abuse that fact by refusing to invest in their grid. These blackouts are happening because rich executives decided to give themselves millions of dollars in bonuses instead of investing in their crumbling infrastructure.” Harder's office said he is exploring potential legislative options regarding the blackouts.

Here we go again. This CANNOT be the new normal. PG&E needs to fix up its infrastructure like they should have a decade ago. https://t.co/2c093Xur4q — Rep. Josh Harder (@RepJoshHarder) October 21, 2019

11:14 a.m. San Mateo County identifies specific areas losing power: County officials said they expect PG&E to cut power to 1,005 addresses, which include 23 medical baseline customers. Areas affected will include portions of Woodside, La Honda and surrounding unincorporated San Mateo County. PG&E said it will cut power starting at noon Thursday and it will likely not take long for power to be restored due to the small number of people affected.

11:11 a.m. What you need to know about PG&E power shut-offs: This story helps explain why PG&E is preemptively cutting power and what readers can do to make their lives easier during a blackout.

11:10 a.m. Check out the San Francisco Chronicle’s Bay Area Outage Map: PG&E’s website crashed numerous times during the last shut-offs, but readers can explore this map to see outages in specific areas in real time.

11:06 a.m. Sonoma County expects power back Thursday, but maybe not: The Sheriff’s Office said in an alert that PG&E expects to turn power back on starting Thursday afternoon, but it could take a couple days for some customers.

Power shutoff confirmed for Sonoma County starting today at 3pm. Full details here: https://t.co/DHXKthnhD5 pic.twitter.com/xwLSl1IzkX — Sonoma Sheriff (@sonomasheriff) October 23, 2019

10:51 a.m. Total number of potential blackouts in the Bay Area: In Napa County, shut-offs could affect 7,488 homes and businesses and 140 medical baseline customers who are dependent on equipment that needs power, according to PG&E. In San Mateo County, 372 customers and 11 medical customers could be affected, while 26,845 customers and 893 medical customers potentially face power cuts in Sonoma County.

10:45 a.m. PG&E weather map shows elevated risk Sunday and Monday: The map below helps monitor weather conditions throughout the company’s service territory, and those conditions determine whether a Public Safety Power Shutoff may be necessary.

10:43 a.m. Sonoma County blackout areas identified: The Sonoma County Sheriff’s Office issued a statement saying PG&E will cut power at 3p.m. in all of portions of the following areas: Annapolis, Boyes Hot Springs, Cloverdale, Fulton, Geyserville, Glen Ellen, Healdsburg, Kenwood, Larkfield, Santa Rosa, Sonoma, Windsor and Stewarts Point.

10:38 a.m. Blackouts could grow worse this weekend: PG&E may implement even more outages starting this weekend. The company’s seven-day shut-off forecast shows an “elevated” likelihood that the company will turn off power in three of nine zones in is service territory on Saturday. On Sunday and Monday, eight of nine zones were listed in the “elevated” category, which is two designations below PG&E actually warning it will turn off power in a given area.

10:34: a.m. Community centers open during power outages: Here is a list of community resource centers in areas that could be affected during the PG&E shut-offs.

10:06 a.m. Power to be cut in North Bay at 3 p.m.: Pacific Gas and Electric Co. announced it will preemptively cut power around 2 p.m. Wednesday in the Sierra Foothills, 3 p.m. in North Bay counties and approximately 1 a.m. Thursday in San Mateo and Kern counties.

Alejandro Serrano is a San Francisco Chronicle staff writer. Email: alejandro.serrano@sfchronicle.com Twitter: @serrano_alej