California's newest wildfire tore through retirement communities built on golf courses and killed elite thoroughbred horses in its first destructive day. The new blaze in San Diego County means a huge swath of Southern California is now in flames after December's shockingly dry, hot, and windy conditions brought on unprecedented fire danger. The Lilac Fire quickly grew to more than 4,000 acres and burned dozens of homes at Rancho Monserate Country Club, the AP reports. Flames engulfed a horse training center, prompting trainers to unlock stables and encourage hundreds of race horses to run for their lives. It's not clear how many died. The region's biggest fire, the Thomas fire 200 miles north, keeps growing and has destroyed more than 400 homes and buildings. (More California wildfires stories.)