San Diego Gas & Electric cut power to more than 7,000 customers as potentially fire-fueling Santa Ana winds picked up across San Diego County Thursday. 

The planned 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.

The shutoffs affected, and may continue to affect, customers in the communities of Barona, Barrett Lake, Black Mountain Ranch, Coronado Hills, East Valley Center, Elfin Forest, Julian, Lake Hodges, Mesa Grande, Mount Laguna, Olivenhain, Palomar Mountain, Rancho Bernardo West, Rancho Santa Fe, San Marcos, Shelter Valley, Viejas, and Warner Springs.

A real-time outage map can be found here.

The power shut-offs 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. 

SDG&E said their Emergency Operations Center is fully staffed and their helitanker is ready to help CalFire, if needed. 

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.

While no fire had erupted in those communities, SDG&E said the move was a "last resort" measure to prevent a wildfire that could spark from downed power lines. 

San Diego County residents were taking their own precautions to prevent wildfires. In Alpine, residents were filling gas canisters to keep generators running. In Fallbrook, up to 42,000 customers in 28 communties were alerted that they could see outages amid while the Red Flag Warning was in effect. 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.

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."

Areas that could be affected include: Alpine, Barona, Barrett Lake, Black Mountain Ranch, Boulevard, Campo, Coronado Hills, Cuyamaca, Descanso, East Poway, East Valley Center, Elfin Forest, Julian, Lake Hodges, Mesa Grande, Mount Laguna, Olivenhain, Palomar Mountain, Pine Valley, Potrero, Ramona, Rancho Bernardo West, Rancho Santa Fe, San Marcos, Santa Ysabel, Shelter Valley, Viejas and Warner Springs.

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.

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."

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.

Steve Dewitt, a deli manager at Pala Mesa Market in Fallbrook, said he likes to remain open during the power outages.

“We are open during a power outage, so it helps our customers that need to come in if they need ice or food, we have backup power and emergency lighting,” said Dewitt.

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.

Winds will peak overnight, when a high wind warning was scheduled to go into effect for the inland valleys, foothills and mountains. 

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.