A woman driving along Dog Bar Road outside Grass Valley hit a patch of black ice early Tuesday morning, toppling her vehicle onto its roof in a ditch, said an official with Nevada County Consolidated Fire District. The woman sustained only minor injuries and was transported to Sierra Nevada Memorial Hospital, said Jim Turner, a battalion chief. “When I was coming La Barr Meadows (Road), I was only going 30 to 25 miles an hour,” Turner said. “Every corner that had shade on it had a patch of ice.” Turner advised drivers that as Nevada County gets into colder temperatures, …