SAN FRANCISCO — In the hours before fire crews were able to corral a wildfire in rural far Northern California, wind-driven flames fueled by dry grass and brush tore through communities at an estimated 500 acres an hour, giving residents just minutes to grab what they could and escape.Sixty-eight residences were destroyed, officials said Thursday, nearly doubling the initial estimate of home losses in Shasta County from the Clover Fire, which began three days earlier around the community of Igo about 150 miles north of Sacramento. Authorities warned that the number could rise further.On Wednesday, officials said they had found a burned body in the fire’s perimeter. Brian Stanley Henry, 56, was found inside a motor home that was destroyed by the fire, officials said. Sheriff’s deputies discovered his body while checking his home in Igo at his family’s request.“It was very destructive in a very short period of time,” state fire spokesman Mike Witesman said.Witesman said the homes were likely destroyed within eight hours of the fire’s start. The blaze damaged an additional five homes and destroyed 128 outbuildings, officials said.It had burned 12 1/2 square miles by Thursday morning and was 75 percent contained.About 300 homes were evacuated, although officials expected to begin lifting at least some evacuations on Thursday.Igo resident Ed Fox felt both fortunate and frustrated as he and his wife, Karen, spent their third full day at a local church that was turned into an evacuation center.