A Roseburg man mowing his lawn in hot, dry weather, started a grass fire Friday evening that burned his barn to the ground and threatened a nearby home, fire officials said Saturday afternoon. Douglas County Fire District No. 2 Fire Marshal Josep Pedrola reported a home at 1058 Troost Street narrowly escaped destruction in the fire, which started when Kevin Kinzer reportedly struck a rock while mowing grass outside his home at about 6:30 p.m. Friday. Kinzer told firefighters he went into his house to change his shoes, unaware that he had created a spark in dry grass, and emerged …