San Diego Gas & Electric cut power to more than twice as many San Diego County homes and businesses early Friday as gusty Santa Ana winds with the potential to fan wildfires peaked overnight.
By Saturday evening, all customers had their power restored, SDG&E announced.
About 16,000 customers were without power by 5 a.m. Friday -- more than double the 7,500 on Thursday. By 8 a.m., close to 20,000 people were without power, but that number fell to 16,000 by 2 p.m. and 16,000 were still without power as of 6:30 p.m. Friday.
SDG&E said the move was a "last resort" measure to prevent a wildfire that could spark from downed power lines.
The shutoffs affected the communitites of Julian, Ramona, Valley Center, Pauma Valley/Cuca Ranch, Descanso, Alpine, Boulevard, Cuyamaca, Guatay, Pine Valley, Jacumba, Santa Ysabel, Potrero, Dulzura, Campo, and Poway, according to SDG&E.
Some of those communities were forced to cancel classes due to the lack of power. Students in the Julian Union, Julian Union High, Mountain Empire Unified and Warner Unified school districts were affected.
Wes Jones, Communication Specialist with SDG&E, said choosing which communities to cut power to is a "tense environment where grid operators are making tough decisions."
The outages could last until 6 p.m. on Saturday because SDGE crews have to inspect all de-energized lines before power can be restored, the agency said. A real-time outage map can be found here.
The Red Flag Warning went into effect at 5 a.m. Thursday and was scheduled until 5 p.m. Friday. During that time, the combination of gusty winds, hot temperatures and low humidity that make the perfect conditions for wildfires to spark and spread rapidly.
A high wind warning was also in effect overnight, when gusty Santa Anas were expected to peak, for the inland valleys, foothills and mountains.
SDG&E said their Emergency Operations Center is fully staffed and their helitanker is ready to help CalFire, if needed.
San Diego County residents were taking their own precautions to prevent wildfires. In Alpine, residents were filling gas canisters to keep generators running.
Alpine resident Gregory Palmer, who lives near Viejas Casino was among the customers who were without electricity Thursday.
Palmer has been evacuated several times during wildfires, so the gusty winds make him nervous.
"I have a generator and I have enough fuel to be about 12 hours," he said. "So if it lasts much more than midnight tonight, Im going to be without unless I make a run down to the gas station."
For Fallbrook resident Cynthia Grey, she says she is prepared as she's dealt with other fires.
“For me it means that I’m going to irrigate and make sure I have a plan, another tip is that I leave my window open at night to smell smoke and hear sirens so that I’m ready to leave,” said Grey.
The forced power shut-offs began for a few hundred customers at about the same time a Red Flag Warning went into effect Thursday morning. By 2:30 p.m., SDG&E cut off power to an additional 3,000+ customers. As of 8:45 p.m., nearly 7,500 customers were without power due to deliberate shutoffs.
Additional outages are possible. Up to 42,000 customers in 28 communties were alerted to potential cut-offs. Customers were not given any scheduled outage time. Instead, SDG&E said they would continue to monitor weather conditions and alert customers if a shut off was necessary.
Nine resource centers will open at 8 a.m. Friday to provide residents with food and water, outlets to charge phones, and access to information.
There will be centers at the Descanso Branch Library, the Whispering Winds Catholic Camp in Julian, the Ramona Branch Library, the Pine Valley Improvement Club, Lake Morena Community Church, Potrero Community Center, Dulzura Community Center and Warner Springs Resource Center. Addresses can be found here.
The Sycuan Casino said their hotel was also without electricity, though their casino floor was running on a back-up generator.
During the fire weather event, winds were expected to average 40 to 50 miles per hour with some isolated gusts reaching 60 mph. In wind-prone passes and canyons, winds could even reach 75 mph, according to NBC 7 Meteorologist Sheena Parveen. Humidity was expected to be less than 10 percent and temperatures were expected to be in the mid-90s to low-100s.
Fire agencies staffed up Thursday to prepare for the hazardous conditions. San Diego Fire-Rescue added two brush-rig strike teams and had crews on overtime for two firefighting helicopters, which would be available for 24-hours a day through Friday evening.
Cal Fire San Diego brought in an extra air tanker to the Ramona Air Base on Wednesday. The agency added an additional eight engines, four water tenders and a helicopter to help in any firefight that arises.
Fall is historically one of the most dangerous times of the year for wildfires in California. Seven of the state's 10-most destructive wildfires occurred in October -- many fueled by monster winds, including Santa Ana gusts.
High temperatures topped 100 degrees at four locaitons in the county Thursday. Highs of 102 were recorded in Santee and Miramar, and Vista and the Oceanside Airport recorded highs of 100.
Some relief is expected on Saturday when winds shift to an onshore flow, ending the Santa Ana event, Parveen said. This will give humidity a chance to recover and allow temperatures to cool.
This week's extreme heat could cause heat exhaustion or heat stroke. The National Weather Service urges residents to drink plenty of water, stay in air-conditioned rooms and stay out of the sun as much as possible.
NBC 7 Weathercaster Ashley Matthews pinpointed some coastal areas that are predicted to have the lowest high temperatures as possible "cool off spots." Those beaches include Encinitas, with a forecasted high of 77 degrees, and La Jolla, with a forecasted high of 78 degrees. For the South Bay, Imperial Beach is expected to see a high temperature of 83 degrees.
For a list of cool zones in San Diego County, click here.