BLY, Oregon—The largest wildfire in the U.S. torched more dry forest landscape in Oregon on Sunday, one of dozens of major blazes burning across the West as critically dangerous fire weather loomed in the coming days. The destructive Bootleg Fire just north of the California border grew to more than 476 square miles (1,210 square kilometers), an area about the size of Los Angeles. Erratic winds fed the blaze, creating dangerous conditions for firefighters, said John Flannigan, an operations section chief on the 2,000-person force battling the flames. “Weather is really against us,” he said. “It’s going to be dry and air is going to be unstable.” Authorities expanded evacuations that now affect some 2,000 residents of a largely rural area of lakes and wildlife refuges. The blaze, which was 22% contained, has burned at least 67 homes and 100 outbuildings while threatening thousands more. At the other end of …