San Diego County will be hit by a second wave of Santa Ana winds Thursday night and early Friday that represent more of a wildfire threat than the gusts that whipped parts of the region early Wednesday, the National Weather Service said. The Santa Anas also will slam Los Angeles County, where wild winds sparked huge wildfires that damaged or destroyed more than 1,000 homes and businesses Tuesday and early Wednesday. In greater San Diego, “the relative humidity will be lower, the winds will be really strong, and the land is critically dry,” said Casey Oswant, a weather service forecaster. ICYMI: What exactly is a red flag warning? What are mountain waves? Wind terms you need to know “The Santa Anas also will be out of the east, which means there could be stronger crosswinds on Interstate 8. The area east of Alpine could get 75 mph gusts, and there could be 50 mph to 60 mph winds in the inland foothills.” The relative humidity will drop to the 15-to-20% level, which is more conducive to the start and growth of wildfires — especially east of Interstate 15, where there is a lot of chaparral, the most flammable kind of vegetation in the U.S. A third, weaker round of Santa Anas could come on Sunday, and there’s the possibility of a fourth on Tuesday or Wednesday, forecasters said. There’s no precipitation in the forecast through Jan. 16, and San Diego is now experiencing the driest start of the rainy season since at least 1850. Only 0.14 inches of rain has fallen since Oct. 1. San Diego Gas & Electric has temporarily shut off electricity to 8,991 of its customers to reduce the chance the strong winds will cause power lines to throw off sparks that could start fires. That number could grow. The utility has notified about 65,000 customers that they face potential outages. Dozens of SDG&E workers were stationed in local canyons and on mountain peaks Wednesday monitoring the winds. On Wednesday, Cal Fire Capt. Robert Johnson said five engines and one hand crew previously sent from Northern California to San Diego County to be on standby had been rerouted to assist Los Angeles County. Johnson reassured residents that another five engines and a hand crew from up north would remain in San Diego County to assist in case of a local emergency. “Even with sending those resources out there, we still have additional staffing in San Diego in the event of a new incident down here,” Johnson said. Local firefighting agencies in San Diego, Poway, Chula Vista, Carlsbad and National City were also sending personnel to L.A. as part of another multi-agency strike team, which consists of four engines with four crew members each. Staff writer Caleb Lunetta contributed to this report.